TeV Particle Astrophysics 2024

Aug 26, 2024, 12:00 AM → Aug 30, 2024, 2:40 PM America/Chicago

University of Chicago

TeV Particle Astrophysics (TeVPA) is an international conference that covers the most recent advances in the field of Particle Astrophysics. This year, TeVPA returns to Chicago for the first time since its inaugural edition in 2005 (at Fermilab). This meeting will feature morning plenary sessions, and afternoon parallels on cosmic ray physics, gamma-ray astronomy, neutrino astronomy, cosmology, direct and indirect searches for dark matter, gravitational waves, and their connection to particle physics.

 

 

 

Plenary speakers: 

 

Hugh Lippincott – Dark Matter Icebergs

Annika Peter – Preparing simulations for the precision era of dark matter cosmology

Chelsea Bartram – Low frequency dark matter waves: a forecast

Noah Kurinsky – Dark Matter Ripples: High-Mass Axions and Low-Mass Fermions

Toshihiro Fujii – The 100 year endeavor for detecting the highest energy cosmic rays

Noemie Globus – Ultra High Energy Cosmic Rays: A Theoretical Review

Zhen Cao – LHAASO Updates in γ-ray Astronomy and CR Measurements (LHAASO Collaboration)

Tracy Slatyer – Where Next for Indirect Dark Matter Searches?

Nick Rodd – An Update on the Galactic Center Gamma-ray Excess

Ke Fang – Galactic and Extragalactic Neutrino Factories

Vera Gluscevic – Dark matter interactions: from the early universe to near-field cosmology

Carmelo Evoli – Galactic Cosmic Ray Leptons: New Results and Insights from TeV Halos

Regina Caputo – A Space-based Gamma-ray Observations for the Next Decade: Where we’ve been and where we’re going

Brian Metzger – Quasi-Periodic Eruptions from Star-Disk Collisions in Galactic Nuclei

Manuel Meyer – The Science Potential of the Cherenkov Telescope Array Observatory

Julian Munoz – Searching for new physics at cosmic dawn

Josh Ruderman – Phases of Particle Dark Matter Production

Kim Boddy – NANOGrav and Gravitational Waves from the Early Universe

Mariangela Lisanti –Galactic dynamics in the era of GAIA

Jessica Turner – Primordial Black Holes and the Early Universe

Philip Bull – 21 cm cosmology

Elisa Resconi – Active Galactic Nuclei as Counterparts of IceCube Neutrinos

Maya Fishbach – Astrophysical Lessons from LIGO-Virgo-KAGRA's Black Holes

Brian Clark – Experimental searches for ultra-high-energy neutrinos

Brian Batell – Probing the dark sector with accelerator experiments

          Gianfranco Bertone – Conference summary talk

 

 

Monday, August 26

8:30 AM Registration

9:00 AM Welcome

Plenary Session

1 The 100-year endeavor for detecting the highest energy cosmic rays

Clarifying origins and acceleration mechanisms of the most energetic particles in the universe has been the 100-year endeavor, being one of the most intriguing mysteries in an interdisciplinary research among astroparticle physics, high-energy physics and nuclear physics. Since ultra-high energy cosmic rays (UHECRs) are deflected less strongly by the Galactic and extra-galactic magnetic fields due to their enormous kinetic energies, their arrival directions would be correlated with their origins. A next-generation astronomy using UHECRs is hence a potentially viable probe to disentangle mysteries of extremely energetic phenomena in the nearby universe.
In this talk, I will give an introduction of cosmic-ray physics, detection techniques, history over 100 years and the latest results of the two giant observatories in operation; Telescope Array experiment and Pierre Auger Observatory including their on-going upgrades. I will also address scientific objectives, requirements and developments for future UHECR observatories.

Speaker: Toshihiro Fujii (Osaka Metropolitan University)

UHECR_TeVPA2024_ToshihiroFujii.pdf

2 A Space-based Gamma-ray Observations for the Next Decade: Where we’ve been and where we’re going

For nearly 20 years, space based gamma-ray observations from the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory have revolutionized our understanding of the universe. They have revealed the explosive death of stars, the creation and evolution of black holes at all scales, and even our understanding of dark matter. However, this has also yielded many more questions. Questions that can only be answered by the next generation of gamma-ray telescopes. In this talk, I will briefly overview some key science topics that have been addressed by Fermi and Swift, the questions that have come out of these observations, and how the space-based gamma-ray community is planning for future observatories including upcoming missions and mission concepts.

Speaker: Regina Caputo (Nasa)

Caputo-GammaRaysInSpace.pdf

10:50 AM Coffee Break

Plenary Session

3 LHAASO Updates in γ-ray Astronomy and CR Measurements (LHAASO Collaboration)

LHAASO keeps operating with high duty cycle and providing unique observations in gamma-ray sources and diffuse charged cosmic rays. Gamma-rays from the BOAT GRB, blazars, near-by AGNs and PeVatrons in our own galaxy are well detected. Physics associated with EBL, new physics searches, radiation mechanism of various sources are discussed. Particle acceleration in the galactic sources and propagation in the Milky Way are investigated using UHE photon measurements. Protons and mixture of protons and α’s are separated from other charge CRs for the measurements of individual spectra and their knees, while the more traditional spectrum, composition and anisotropy of all charged CR particles are measured. Future prospects of the LHAASO experiment is also presented in this talk.

Speaker: zhen cao (Institute of High Energy Physics)

4 New Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

We present new results in the search for WIMP dark matter-induced nuclear recoils using a 4.2 tonne year exposure of the LZ experiment, which operates on the 4850’ level of the Sanford Underground Research Facility.

Speaker: Scott Haselschwardt (University of Michigan)

lz_results_tevpa.pdf

12:30 PM Lunch

Parallel Session: Cosmic Rays

Conveners: Benedikt Schroer (The University of Chicago), Luca Orusa

5 A Method to Investigate Potential Time Variation in the Cosmic-Ray Anisotropy

There is an observed anisotropy in the arrival direction distribution of cosmic-rays in the TeV-PeV region with variations on the scale of one part in a thousand between different areas of the sky. Though the origin of this anisotropy is an open question a possible factor is cosmic-ray interactions with interstellar and heliospheric magnetic fields. These magnetic fields may change over time - for example, due to changes in solar activity over the course of its 11 year solar cycle. The cosmic-ray anisotropy can reflect these time-dependent magnetic fields. We describe a general, model-independent method to detect time variations in the cosmic-ray anisotropy. The methodology is then validated using 1/12 of the cosmic-ray data taken by the IceCube Neutrino Observatory from 2012 through 2023.

Speaker: Perri Zilberman (University of Wisconsin-Madison)

TeVPA_2024_PZilberman.pdf

6 Properties of Cosmic H, He, Li and Be Isotopes Measured by the Alpha Magnetic Spectrometer

We present the measurements of cosmic H, He, Li and Be isotopes based on AMS data. We observed that over the entire rigidity range D exhibits nearly identical time variations with p, $^3$He, and $^4$He fluxes. Above 4.5 GV, the D/$^4$He flux ratio is time independent and its rigidity dependence is well described by a single power law $\propto$ R$^\Delta$ with $\Delta^4$D/$^4$He = $−0.108 \pm 0.005$. This is in contrast with the $^3$He/$^4$He flux ratio for which we find $∆_{^3\mathrm{He}/^4\mathrm{He}} = −0.289 \pm 0.003$. The significance of $\Delta^4$D/$^4$He > $∆_{^3\mathrm{He}/^4\mathrm{He}}$ exceeds $10\sigma$. In addition, we found that above $\sim$13 GV the rigidity dependence of D and p fluxes is identical with a D/p flux ratio of $0.027 \pm 0.001$. These unexpected observations indicate that contrary to expectations, cosmic deuterons have a sizeable primary component. The Li and Be isotopic compositions provide crucial complementary information on cosmic ray propagation and sources. The $^7$Li/$^6$Li ratio tests the origin of Li nuclei in cosmic rays. As the radioactive isotope $^{10}$Be decays to $^{10}$B with a half-life comparable to the cosmic-ray residence time in the Galaxy, the $^{10}$Be/$^9$Be ratio can be used to measure the cosmic-ray propagation volume. Current measurements of the $^7$Li/$^6$Li, and $^{10}$Be/$^9$Be ratios are limited to energies below 2 GeV/n and are affected by large uncertainties. We present the measurement of the $^6$Li and $^7$Li fluxes and their ratio, and of the $^7$Be, $^9$Be, $^{10}$Be fluxes and their ratios in the energy region ranging from 0.6 GeV/n to 12 GeV/n.

Speaker: Jiahui Wei (Shandong Institute of Advanced Technology (SDIAT))

AMS_Isotope_TeVPA.pdf

7 Heritage and challenges for next generation charged cosmic-ray space missions

The current generation of Charged Cosmic Ray (CCR) experiments in operation in space (e.g. AMS-02, DAMPE, CALET) is providing novel information and is measuring unexpected features that are challenging the phenomenological community to revisit the paradigms behind the established theories of cosmic-ray origin, acceleration and propagation, and to formulate comprehensive models able to consistently explain all the observed structures.
This achievement has been made possible thanks to the observation of features in cosmic-ray spectra unveiled by the high granularity (in energy and in time), high resolution and high statistics measurement of all the CCR components, in a wide range of energies (O(GeV) - O(100 TeV)).
Leveraging on the experience and on the heritage of the current detector generation, several new ideas to further improve, and possibly lead to a breakthrough, the field are being studied, developed, and being applied.
The first two experiments benefiting of these novel ideas are the AMS-02 experiment with its "Layer0 Upgrade" (2026) and the HERD experiment to be installed on the Chinese Space Station (2026 - 2027). The same concepts, in addition to other technological steps forward, are also being applied to the design of a new generation of revolutionary CCR experiments (e.g. ALADInO and AMS-100).
The lessons learned from the operations of the current generation of CCR detectors and the perspectives for future CCR space missions will be reviewed and discussed.

Speaker: Matteo Duranti (INFN Perugia (IT))

TheDesignOfFutureCosmicRaySpaceExperiments_nobackup.pdf

8 The energy spectrum of ultra-high energy cosmic rays measured using the Pierre Auger Observatory

The measurement of the energy spectrum of ultra-high-energy cosmic rays (UHECRs) is an essential step towards understanding their acceleration, propagation and intergalactic origin.
With the Pierre Auger Observatory, it is possible to probe UHECRs with energies up to $10^{20}\,$eV and beyond.
Located in Argentina it comprises more than 1600 water Cherenkov detectors spread over an area of 3000 square kilometers overlooked by Fluorescence detectors.
Starting in 2004 the first phase of the Observatory’s data-taking finished in the end of 2021 accumulating an exposure of about $80 000\,\text{km}^2\text{sr\,yr}$.
In this contribution, we present the measurements of the cosmic-ray energy spectrum from the Phase I data analysis.
The hybrid detector layout of the Pierre Auger Observatory with surface detector arrays of different densities enables the coverage of a wide energy range.
Features observed by other experiments, such as the "second knee" at around $200\,$PeV, the "ankle" at $5\,$EeV and the steepening at $50\,$EeV are highly significant.
Moreover, a new feature has been identified above the "ankle".
Between $2.5\times10^{18}\,$eV and $5\times10^{19}\,$eV the measurement is the most precise made so far as the accumulated exposure is large enough so that the flux measurement is dominated by systematic uncertainties.
Additionally, the combined fit of the measured energy spectrum, shower maximum depth distributions and arrival directions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models and source distributions.
All in all, the Phase I results comprise a major step forward in the understanding of the UHECRs and establish the cornerstone for upcoming Phase II studies with the upgraded AugerPrime detector.

Speaker: Fiona Ellwanger (Karlsruhe Instiute of Technology - Institut für Astroteilchenphysik)

tevpa_slides_compressed.pdf

tevpa_slides.pdf

Parallel Session: Direct Detection

Convener: Leah Jenks (The University of Chicago)

9 Status update on the XENONnT experiment

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. XENONnT, a dual-phase xenon time-projection chamber, is one of the leading experiment in search for Weakly Interacting Massive Particles (WIMPs) and many other search for rare events. In this talk, I will give an introduction to XENONnT experiment and report about recent progress in the search for Dark Matter and other rare events.

Speaker: Lanqing Yuan (UChicago)

xenon_tevpa_20240826.pdf

10 On track for discovery of sub-GeV dark matter with liquid xenon TPCs

Sensitivity to detecting sub-GeV dark matter in liquid xenon TPCs has been limited by instrumental backgrounds, namely delayed electron noise. For more than a decade, attempts to mitigate this background have proved inconclusive. In this talk, we will show new data that enlightens the mechanism of delayed electron noise, as well as pathways to its removal. With the assumption that this background can be eliminated, we present sensitivity projections for sub-GeV dark matter candidates, including hidden sector models.

Speaker: Ryan Gibbons (University of California, Berkeley)

tevpa 2024.pdf

11 Backgrounds in the LUX-ZEPLIN (LZ) Experiment

The LUX-ZEPLIN (LZ) experiment is actively collecting data to look for evidence of WIMP-like dark matter. The experiment, which consists of a dual-phase 10-tonne xenon detector and a veto system, has been carefully designed to mitigate radioactive and instrumental backgrounds. Any remaining sources of background, which can mimic dark matter interactions, must be systematically characterized and understood. I will discuss the contributions of these backgrounds, as well as mitigation techniques, in the context of various searches with the LZ experiment.

Speaker: Ann Wang (Stanford/SLAC)

TeVPA2024_LZBackgrounds_AWang.pdf

12 Search for atmospheric millicharged particles using the LUX-ZEPLIN detector

"We report on a search for millicharged particles (mCPs) produced in cosmic ray proton atmospheric interactions using data collected during the first science run of the LUX-ZEPLIN experiment.
The mCPs produced by two processes---meson decay and proton bremsstrahlung---are considered in this study. This search is sensitive to mCPs with masses in the range between 90 MeV/c$^2$ -- 1100 MeV/c$^2$, and with fractional charges greater than $10^{-3}$ that of the electron charge (\textit{e}).
With an exposure of 60 live days and a 5.5~tonne fiducial mass, we observed no significant excess over background. This is the first experimental search for atmospheric mCPs and the first search for mCPs using an underground liquid xenon experiment.
An upper limit of $2\times10^{-3}$~\textit{e} on the charge has been placed on mCPs with a mass of 100 MeV/c$^2$ at $90\%$ confidence level. Within the 100 to 600 MeV/c$^2$ mass range, this result is competitive with published experimental constraints from beam experiments. "

Speaker: Yongheng Xu (University of California, Los Angeles)

LZmCP_TeVPA_YonghengXu.pdf

13 A Review of NEST Models, and Their Application to Particle Identification

Direct dark matter searches necessitate low backgrounds. Experiments using the noble liquids xenon and argon have obtained very low background levels, but along with the development of the single and dual-phase technologies there has been a continued effort in the community to better understand the detailed scintillation and ionization responses of noble liquids in the presence of low-energy particles, as a function of energy, dE/dx, electric fields, and particle type. As this body of knowledge is reaching a mature state, a unified, predictive software framework for simulating the production of quanta in these detectors is strongly needed. In this talk, I will discuss the current status of NEST: Noble Element Simulation Technique, which is a simulation package based on reasonable empirical models informed by the world's best data on the subject. I will present on the methods used for modeling electronic recoils, nuclear recoils, and quantification of the misidentification of the former as the latter, the primary means of determining the ability to discriminate against residual backgrounds. I will compare NEST models to data, and use TeV-scale WIMPs as an example of a possible signal. Although the focus will be on xenon, existing work on argon will be summarized.

Speaker: Greg Rischbieter

NEST_TeVPA2024_GRischbieter.pdf

Parallel Session: HE Astro / Gravitational Waves

Conveners: Ariane Dekker (The University of Chicago), Christopher Eckner (Center for Astrophysics and Cosmology, University of Nova Gorica)

14 Neutrino and Electromagnetic Signals from TDE Isotropic Winds and Relativistic Jets

The potential association between the tidal disruption event (TDE) AT2019dsg and high-energy astrophysical neutrinos implies the acceleration of cosmic rays. In addition to neutrinos, these accelerated particles could initiate electromagnetic (EM) emissions spanning from radio, optical/UV, X-ray to GeV energies by leptonic and hadronic processes. In this talk, I will present our recent results on the joint analysis of the neutrino and EM cascade emissions from neutrino-coincident TDEs in an isotropic wind model. I will show that the Fermi gamma-ray upper limits could constrain the size of the radiation zone and the maximum energies of accelerated cosmic rays. Moreover, I will discuss our latest work on modeling the multi-wavelength emissions from the jetted TDE AT2022cmc. We systematically study the dynamics of the jet and wind in an external density profile, considering the continuous energy injection rate associated with the time-dependent accretion rates before and after the mass fallback time. We investigate the multi-wavelength emissions from both the jet’s forward shock and reverse shock regions, as well as from the wind, in a self-consistent manner. I will show that the X-ray spectra and fast-decaying light curves extending to 400 days after the disruption can be well described by the electron synchrotron emission from the jet’s reverse shock.

Speaker: Dr Chengchao Yuan (DESY)

15 Large-Scale Environments in BL Lac objects: Connecting Gamma-Ray Absorption Features to Neutrino Production

Exploring large-scale environments in active galactic nuclei (AGNs) typically relies on the analysis of absorption and emission lines in their optical spectrum. However, in BL Lac objects - a category of AGNs with the relativistic jet pointing directly to the observer - the dominant non-thermal emission from the relativistic jet obscures the optical spectrum. Consequently, identifying the optical thermal emission of photon fields emitted by large-scale environmental structures becomes challenging.
Despite this complexity, these environmental photon fields may interact with gamma rays of the blazar jet through gamma-gamma pair production. This interaction reduces the original flux of gamma rays emitted by the source and produces observable absorption features in its spectral energy distribution. Interestingly, the same photon fields can trigger proton-photon interactions, acting as targets for the production of high-energy neutrinos.
In this contribution, we discuss the crucial role of gamma-ray observations in unveiling absorption features in the spectra of BL Lac objects, and we will demonstrate how these absorption features are directly connected to the production of high-energy neutrinos. Additionally, we will present a set of simulations that will investigate the most effective physical conditions that produce fluxes of neutrinos compatible with the sensitivities of the current and the next generation of neutrino detectors.

Speaker: Luca Foffano (INAF)

LucaFoffano_TeVPA2024_neutrinos_260824_upload.pdf

16 Investigating the origin of the TeV gamma-rays in the PeVatron 1LHAASO J2002+3244u

Studying UHE $\gamma$-ray sources and their emission provide insights into the source of the most energetic ($\sim$ PeV) particles, which is key in identifying the origin of the galactic cosmic-ray spectrum. Recently, the Large High Altitude Air Shower Observatory (LHAASO) collaboration published the largest to-date catalog of UHE $\gamma$-ray sources. While most of the sources are either identified as Pulsar Wind Nebulae (PWNe) or Supernova Remnants (SNRs), many remain unidentified. One such source is 1LHAASO J2002+3244u; coincident with radio SNR G69.7+1.0 and a GeV Fermi source. To identify the origion of the emission --whether it is leptonic or hadronic--, we analyzed newly acquired JVLA data of the field around the TeV source, and in this talk, I will present our findings and their implications.

Speaker: Moaz Abdelmaguid (New York University)

TeVPA_Conference.pdf

17 Impact of cosmic rays on the pair beam instability from TeV blazars

TeV gamma rays from blazars interact with the extragalactic background light and produce ultrarelativistic, strongly forward-directed $e^+e^-$ pairs. The (in)stability of these pair beams is important for intergalactic magnetic field (IGMF) constraints, the distribution of secondary gamma rays, and the thermal evolution of the intergalactic medium (IGM). Pair beams drive a linear instability of plasma oscillations at wave numbers $k\approx \ell_{\rm s}^{-1}\sec\theta$ ($\theta$ being the angle between the beam and wave vector, and $\ell_{\rm s}$ being the skin depth). We introduce another ingredient in the physics of pair beams: the cosmic ray electrons in the IGM. The $\sim$MeV gamma ray background can Compton scatter off of thermal electrons in the IGM, thus acting as a “guaranteed” source of cosmic ray electrons even in regions of the IGM that have not yet been shocked. We estimate that these electron cosmic rays contribute $\sim0.3\%$ of the IGM pressure at $z=2$, rising to $\sim2\%$ today. We find that these electrons cause linear Landau damping of plasma oscillations, with damping times of order $\sim 10^6$ s at wave numbers of $(1.2-5)\ell_{\rm s}^{-1}$ at cosmic mean density at $z=2$. This is orders of magnitude faster than the pair beam-driven instability can develop; it thus turns off the pair beam instability except for modes with very small $\theta$ (wave vector along the beam direction, where linear Landau damping is kinematically suppressed). We discuss ongoing work on the fate of this narrow range of modes that remain linearly unstable.

Speaker: Christopher Hirata (The Ohio State University)

pairbeams_TeVPA2024.pdf

18 The multiwavelength signature of the multizone jets of Mkn 421

Active galactic nuclei (AGN) power relativistic outflows that remain collimated over kiloparsec scales. These outflows, known as jets, accelerate cosmic rays (CRs) to high energies, exceeding the PeV regime, and potentially contribute significantly to the observed CR spectrum on Earth. As CRs interact with their surrounding medium, they produce multiwavelength (MW) emission spanning over ten orders of magnitude in photon energy, from radio waves to TeV gamma rays. Leptonic CRs contribute to the entire MW flux through synchrotron radiation and inverse Compton scattering. Hadronic CRs, through inelastic collisions with the ambient gas and photon fields, initiate particle cascades that lead to gamma rays and neutrinos. Markarian 421 (Mkn 421), one of the most well-studied AGN in the non-thermal Universe, launches a jet along the line of sight, making it one of the brightest gamma-ray objects in the sky. In this work, we present a new multizone jet model that can explain both the steady-state MW spectrum and the flaring states of Mkn 421. Using Monte Carlo statistical analysis, we compare the jet dynamics of a MW spectrum of leptonic nature to one of hadronic nature. Finally, we discuss the radiative signature emerging from the interaction between the jets and a dark matter halo surrounding the emitting jet regions.

Speaker: Dimitrios Kantzas (LAPTh/CNRS)

kantzas_compressed.pdf

Parallel Session: Indirect Detection

Conveners: Elena Pinetti (Fermilab), Yitian Sun (MIT)

19 Emulation of cosmic-ray antideuteron fluxes from dark matter annihilation

Cosmic-ray antimatter, particularly low-energy antideuterons, constitute a sensitive probe of dark matter annihilating in our Galaxy. We study this smoking-gun signature and explore its complementary to indirect search via cosmic-ray antiprotons. We revisit the Monte Carlo simulation of antideuteron coalescence and cosmic-ray propagation, allowing us to assess uncertainties from both processes. In particular, we incorporate uncertainties in the $\Lambda_b$ production rate and the coalescence momentum and consider two distinctly different propagation models. To this end, we further the development of the neutral emulator DarkRayNet enabling a fast prediction of propagated antideuteron energy spectra for a wide range of annihilation channels and any admixtures thereof. We find that our network can predict the various spectra with excellent accuracy, offering a significant speed-up over the full simulation. Employing the network's output, we then test the detectability of antideuterons from dark matter annihilation with AMS-02 and the upcoming GAPS experiment for a wide range of dark matter masses.

Speaker: Lena Rathmann (RWTH Aachen University)

TeVPA2024_Rathmann.pdf

20 Indirect Dark Matter Searches with GAPS experiment

Indirect dark matter searches are novel ways of dark matter detection that differ from collider and direct dark matter searches. Information beyond standard model physics can potentially be obtained by focusing on the daughter particles generated from potential DM-DM interaction,

GAPS(General Antiparticle Spectrometer) is a balloon-borne indirect dark matter search experiment mainly searching for signals of dark matter from low-energy (kinetic energy $<=$ 0.25 GeV/n) cosmic antinuclei. In particular, antideuteron production from standard astrophysical processes has a low intensity in our target energy range, giving us an almost background-free signal of dark matter annihilation and decay. GAPS flight will also offer antiproton low energy range measurements to give us new constraints. GAPS will have the capability of measuring low-energy antihelium-3 for potentially exciting new discoveries.

The active detectors of GAPS are composed of 1000 lithium-drifted silicon detectors and two layers of plastic scintillator working as time-of-flight to determine the particle velocity and direction. Currently, GAPS is being fully integrated and undergoing calibration and testing in preparation for its first Antarctic balloon flight in the austral summer of 2024. This talk will introduce indirect dark matter searches with the GAPS experiment and report the current status of the GAPS instrument, including ground testing results.

Speaker: Jiancheng Zeng (Northeastern University)

240815_TeVPa2024_GAPS_JC.pdf

21 VERITAS Observations of Dark Matter Subhalo Candidates

Imaging Atmospheric Cherenkov Telescopes (IACTs) continue to be one of the best instruments to search for dark matter indirectly. One of the key criteria to an effective search is the selection of sources. In the past, these sources have been selected based on their high J-factors (e.g. the galactic center and dwarf spheroidal galaxies) but after many deep searches, IACTs have yet to find any dark matter signal from any of these sources. In many cosmological simulations, one of the natural outputs is a series of dense substructures located nearby which may have higher J-factors than even some dwarf spheroidals and could be detectable by both Fermi-LAT and VERITAS. We have performed a search for such candidates in the Fermi-LAT catalog and have observed the strongest canidates with VERITAS to confirm or refute their dark matter origin. We will discuss some of the unique signatures and parallel science benefits that can be obtained in such a study using three new candidates as examples.

Speaker: Matthew Lundy (McGill University)

2024_DarkMatter_TeVPA.pdf

2024_DarkMatter_TeVPA.pdf

22 Updated Dark Matter Annihilation Search from Dwarf Galaxies with HAWC

Dwarf Spheroidal (dSphs) galaxies are suspected dark matter dense sources within our galactic neighborhood. They are otherwise quiet locations that are low of other high energy gamma-ray sources which makes them ideal dark matter targets. HAWC's previous dark matter search toward dSph was performed with older reconstruction techniques and significantly less data. This iteration leverages HAWC's improved energy estimation methods and sensitivity at high zenith angles. We also incorporate improved particle physics models and ultra-faint dwarves. This study is over a heavy dark matter regime not well explored ranging from 1 TeV to 10 PeV in dark matter mass. In the case of a null result, we set limits on the velocity-weighted cross section.

Speaker: Daniel Salazar-Gallegos (Michigan State University)

TeVPA2024.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Donglian Xu (Tsung-Dao Lee Institute)

23 IceCube: from the IceCube Upgrade to IceCube-Gen2

IceCube is actively working on a two-phased upgrade program. The IceCube 7-string Upgrade construction is underway: the detector instrumentation, from DOMs to cables and software, is being prepared for the 2025/26 South Pole field season when all of that is planned to come together to form a functioning detector 2700 m below the surface, in fewer than three months. It will provide unprecedented sensitivity to atmospheric neutrinos at a threshold of 3 GeV. It will also allow to refine the calibration of IceCube. Surface detectors are planned to maintain and improve the IceTop array.
In the meantime, the collaboration is actively working on the IceCube-Gen2 program. A Technical Design Report has been completed. The scope of the wide band-neutrino facility, 120 strings, a cosmic ray detector, and a large radio array covering TeV to EeV energies will improve the sensitivity to point sources by a factor of five. I will also discuss how challenges of construction at the South Pole will be met.

Speaker: Prof. Albrecht karle (University of Wisconsin-Madison)

TeVPA2024_Karle_IceCube-Gen2.pdf

24 Evidence of Neutrino Excess from a Population of X-ray Bright non-Blazar AGNs in the Northern Sky with 13 Years of IceCube Data

The IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the South Pole instrumenting deep Antarctic ice. Uncovering the origin of high-energy astrophysical neutrinos is one of IceCube's major goals. We analyze a data sample of through-going track events produced by charged-current muon-neutrino interactions recorded between 2010 and 2023, focusing on the search for individual neutrino point-sources in the Northern sky. Given the 4.2 $\sigma$ evidence for neutrino emission from NGC 1068, which is classified as a Seyfert galaxy and is especially bright in the X-ray emission band, and other IceCube results suggesting correlations between keV X-rays and TeV neutrinos predicted by theoretical models, we additionally search for neutrino emission from X-ray bright, non-blazar active galactic nuclei (AGNs). The catalog selection criteria were updated compared to previous studies, resulting in 47 candidate sources (excluding NGC 1068). In this contribution, we present an updated measurement of neutrino emission from NGC 1068 at a global significance of 4.0 $\sigma$ and evidence of neutrino excess from a population of newly selected X-ray bright, non-blazar AGNs at the 3.3 $\sigma$ level of significance.

Speaker: Tomas Kontrimas (Technical University of Munich (TUM))

tevpa_20240826_seyferts_kontrimas.pdf

25 The Payload for Ultrahigh Energy Observations: Overview and Updates

The Payload for Ultrahigh Energy Observations (PUEO) is a balloon-borne experiment that is designed to achieve world-leading sensitivity to ultrahigh energy (>1 EeV) astrophysical and cosmic neutrinos. Neutrino observations at this energy would provide valuable insights into both astrophysical sources and fundamental physics at extreme-energy scales. To do this, PUEO will leverage the Askaryan effect to observe the radio signals generated by neutrino interactions in the Antarctic ice. The payload’s design builds on that of the four successful flights of the Antarctic Impulsive Transient Antenna (ANITA) balloon program. Improvements implemented in PUEO’s design include the use of a phased-array trigger, real-time digital filtering, more antennas with longer baselines, and a dedicated low-frequency instrument, amongst others. PUEO is now under construction, and is scheduled to fly over Antarctica in late 2025. In this talk I will discuss PUEO’s science goals, the PUEO instrument, and the project timeline.

Speaker: Lucas Beaufore (The Ohio State University)

VFinal The Payload for Ultrahigh Energy Observations TeVPA.pdf

26 A Combined Fit of Ultra-High-Energy Cosmic Rays and Neutrinos from Pierre Auger and IceCube Observatories

The energy density of ultra-high-energy cosmic rays is at the same level as that of high-energy neutrinos measured at IceCube, suggesting a plausible common origin scenario. Here, we report a combined fit utilizing data from the Pierre Auger and the IceCube Neutrino Observatories to test this hypothesis. We incorporate flux and mass composition, including 𝑋max distributions, for energy bins ranging from 10^17.8 to 10^20 eV for cosmic rays, as well as neutrino data at the highest energies, including starting events, partially-contained cascades, and through-going tracks.

Speaker: Lu Lu (University of Wisconsin-Madison)

TeVPA_CombinedUHEFit_2024.pdf

27 Revealing the production mechanism of high-energy neutrinos from NGC 1068

The detection of 1.5-15 TeV neutrino signals from the nearby Seyfert galaxy NGC 1068 by the IceCube Collaboration provides evidence of nonthermal processes at the heart of a supermassive black hole. In this talk, I discuss the possible production mechanisms, taking into account the constraints from neutrino and electromagnetic observations (Fermi-LAT, MAGIC, NuSTAR, etc.). We utilize the Astrophysical Multimessenger Emission Simulator to simulate the electromagnetic cascade processes taking place in the source. I show that only the hadronic scenario is viable, and rule out leptonic and beta decay scenarios. I also present constraints on the emission radius and the cosmic ray luminosity required to explain the observed neutrino luminosity, and discuss the viability of different models for cosmic ray acceleration.

Speaker: Abhishek Das (The Pennsylvania State University)

TeVPA_Abhishek_v3.pdf

Parallel Session: Particle Physics / Cosmology

Conveners: Huangyu Xiao (KICP and Fermilab), Joshua Foster (Massachusetts Institute of Technology)

28 Electron Trap as a meV Axion and Dark Photon Dark Matter Detector

Detecting axion and dark photon dark matter in the milli-eV mass range has been considered a significant challenge due to its frequency being too high for high-Q cavity resonators and too low for single-photon detectors to register. I will present a method that overcomes this difficulty (based on recent work arXiv:2208.06519) by using trapped electrons as high-Q resonators to detect axion and dark photon dark matter and set a new limit on dark photon dark matter at 148 GHz (~0.6meV) that is around 75 times better than previous constraints by a 7 days proof-of-principle measurement. I will also propose some updates to this work that greatly improve the result by optimizing some of the experimental parameters and techniques.

Speaker: yawen xiao

Yawen_TeVPA2024.pdf

29 Gamma rays from supernova axions converting in stellar magnetic fields

Proto-neutron stars, formed in the center of Type-II supernovae, represent promising science targets for probing axions. The hypothetical particles are emitted via e.g. the Primakoff process and can modify the cooling rate of the proto-neutron stars and also convert to observable gamma rays while propagating through astrophysical magnetic field. Observations of Supernova 1987 (SN 1987A) from the Solar Maximum Mission (SMM) gamma-ray telescope have previously been used to set bounds on the axion-photon coupling. In this work, we present updated limits with SMM data by including nucleon-nucleon bremsstrahlung as an additional mechanism of axion production. We also consider a novel axion conversion mechanism in the progenitor magnetic field of SN 1987A. This allows constraining larger axion masses and smaller axion-photon couplings due to the stronger magnetic field of the progenitor star compared to the magnetic field of the Milky Way. We use these results to project the sensitivity of gamma-ray searches towards a future Galactic supernova with a proposed full-sky gamma-ray telescope network.

Speaker: Yujin Park (University of California, Berkeley)

TeVPA2024_Yujin.pdf

30 MicroBooNE's Beyond Standard Model Physics Program

MicroBooNE is an 85-tonne active mass liquid argon time projection chamber (LArTPC) at Fermilab. The detector, with an excellent calorimetric, spatial and energy resolution, has collected beam data from two different beamlines between 2015 and 2020. Additionally, it has collected data when no neutrino beam was running. These characteristics make MicroBooNE a powerful detector not just to study neutrinos, but also for Beyond the Standard Model (BSM) physics. The collaboration recently published searches for heavy neutral leptons and low-mass dark matter that gives rise to dark trident processes. In addition, MicroBooNE has developed tools for a neutron-antineutron oscillation search for the upcoming Deep Underground Neutrino Experiment (DUNE). This talk will highlight MicroBooNE’s recent BSM physics results and explore future searches.

Speaker: Lee Hagaman (The University of Chicago)

lee_hagaman_tevpa_uboone_bsm.pdf

31 Interplay among gravitational waves, dark matter and collider signals in the singlet scalar extended type-II seesaw model

We study the prospect of simultaneous explanation of tiny neutrino masses, dark matter (DM), and the observed baryon asymmetry of the Universe in a $Z_3$-symmetric complex singlet scalar extended type-II seesaw model. The complex singlet scalar plays the role of DM. Analyzing the thermal history of the model, we identify the region of the parameter space that can generate a first-order electroweak phase transition (FOEWPT) in the early Universe, and the resulting stochastic gravitational waves (GW) can be detected at future space/ground-based GW experiments. First, we find that light triplet scalars do favor an FOEWPT. In our study, we choose the type-II seesaw part of the parameter space in such a way that light triplet scalars, especially the doubly charged ones, evade the strong bounds from their canonical searches at the Large Hadron Collider (LHC). However, the relevant part of the parameter space, where FOEWPT can happen only due to strong SM doublet-triplet interactions, is in tension with the SM-like Higgs decay to a pair of photons, which has already excluded the bulk of this parameter space. On the other hand, the latest spin-independent DM direct detection constraints from XENON-1T and PANDA-4T eliminate a significant amount of parameter space relevant for the dark sector assisted FOEWPT scenarios, and it is only possible when the complex scalar DM is significantly underabundant. In short, we conclude from our analysis that the absence of new physics at the HL-LHC and/or various DM experiments in the near future will severely limit the prospects of detecting a stochastic GW at future GW experiments and will exclude the possibility of electroweak baryogenesis within this model.

Speaker: Subhojit Roy (Argonne National Laboratory)

TeVPA2024_subhojit_roy.pdf

32 Cosmological case study of a tower of neutrino states

In this talk, we discuss the cosmological effects of a tower of neutrino states (equivalently a tower of warm dark matter ) on cosmic microwave background (CMB) and large-scale structure. For concreteness, we considered the $N$-Naturalness model which is a proposed mechanism to solve the electroweak Hierarchy problem. The model predicts a tower of neutrino states, which act as warm dark matter, with increasing mass and decreasing temperature compared to the standard model neutrino. Compared to a single neutrino state, such a neutrino tower induces a more gradual suppression of the matter power spectrum. The suppression increases with the total number of states in the neutrino tower.
We explore these effects quantitatively in the scalar $N$-naturalness model and show the parameter space allowed by the CMB, weak lensing, and Lyman-$\alpha$ dataset. We found that neutrinos-induced suppression of the power spectrum at the small scale puts stringent constraints on the model. We emphasize the need for a faster Boltzmann solver to study the effects of the tower of neutrino states on smaller scales.

Speaker: Subhajit Ghosh (The University of Texas at Austin)

SG_TeVPA_2024.pdf

33 Minimal Dark Matter Freeze-in with Low Reheating Temperatures (Implications for Direct Detection

In this presentation, I will investigate the influence of the reheating temperature of the visible sector on the freeze-in dark matter (DM) benchmark model for direct detection experiments, where DM production is mediated by an ultralight dark photon. I will consider a new regime for this benchmark where the initial temperature of the thermal Standard Model (SM) bath to be below the DM mass. The production rate from the SM bath is drastically reduced due to Boltzmann suppression, necessitating a significant increase in the portal coupling between DM and the SM to match the observed relic DM abundance. This enhancement in coupling strength increases the predicted DM-electron scattering cross section, making freeze-in DM more accessible to current direct detection experiments

Speaker: Gabriele Montefalcone (UT - Austin)

TeVPA_gabriele_montefalcone.pdf

3:45 PM Coffee break

Parallel Session: Cosmic Rays

Conveners: Benedikt Schroer (The University of Chicago), Kathryn Plant (NASA JPL/ Caltech), William Luszczak (Ohio State University)

34 Anisotropy in the Arrival Direction of UHECRs: Latest Results from the Pierre Auger Observatory

Ultra-high-energy cosmic rays (UHECRs) are the most energetic messengers in the Universe, with energies reaching up to 10$^{20}$ eV. More than half a century after their discovery, the origins of UHECRs remain an open question. Investigating anisotropies in their arrival directions is crucial to unraveling this mystery. The Pierre Auger Observatory, located in Mendoza, Argentina, is the largest cosmic-ray experiment ever constructed, spanning an area of 3000 km². Designed as a hybrid detector, it has been collecting data for nearly two decades. In this contribution, we present a selection of the latest results on anisotropy in the arrival directions of UHECRs. At small and intermediate scales, we provide updates on the all-sky blind search for localized excesses, the study around the Centaurus region, and the likelihood analysis using catalogs of candidate sources. Additionally, we have examined regions where the Telescope Array Collaboration reported hints of excesses and found no significant effects in those directions with a comparable data set. At larger angular scales, we update the dipolar and quadrupolar amplitudes in various energy bins. We also discuss future prospects for these searches, focusing on increased statistics and the anticipated inclusion of event-by-event mass estimators through the AugerPrime upgrade.

Speaker: Joao deMelloNeto (Universidade Federal do Rio de Janeiro (UFRJ))

Auger_anisotropy_TEVPA2024.pdf

35 Mass Composition Interpretation with the Pierre Auger Observatory

The Pierre Auger Observatory is the largest detector for measuring ultra-high-energy cosmic rays. Located in Argentina and spanning over 3000 square kilometers, the Observatory samples the particle content of Extensive Air Showers using an array of Water-Cherenkov Detectors (WCDs). The shower longitudinal profile is measured with Fluorescence Detectors. In this contribution, the interpretations of the mass composition of ultra-high-energy cosmic ray flux based on data collected by the Pierre Auger Observatory are reviewed. Moreover, we present the evolution of the mean mass of cosmic ray primaries with primary energy, using independent measurements of the depth of the shower maximum, $⁡X_{\max}$​, made with various detectors of the Observatory, including the Auger Engineering Radio Array (AERA). Additionally, we highlight the recent results from deep neural networks trained on WCD data, which enabled a tenfold increase in statistics at the highest energies, providing unprecedented precision for mass estimation at these energies. The tension between the mass composition inferred from $X_{\max}$​ and other shower observables is addressed. Finally, we examine the potential of AugerPrime, the upgrade of the Pierre Auger Observatory, to improve the precision of mass composition measurements.

Speaker: Miguel Alexandre Martins (Instituto Galego de Física de Altas Enerxias)

MAM_MassCompAuger_TeVPA2024_26082024.pdf

36 AugerPrime - the new Phase of the measurements at the Pierre Auger Observatory

The Pierre Auger Observatory is an experiment dedicated to the detection of ultra-high-energy cosmic rays (UHECRs), which have energies higher than the limits reached at the most powerful particle accelerators. Such high-energetic particles can be indirectly detected by measuring extensive air showers using several detection techniques. At the Pierre Auger Observatory, a hybrid technique consisting of a water-Cherenkov detector array combined with fluorescence telescopes was used for almost two decades, comprising the Phase I data. The analysis of this dataset led to major advances in our understanding of the nature of UHECRs. For instance, the existence of the suppression in the spectrum with high accuracy was confirmed, although the origin of this suppression remains nonetheless not understood. As there are still open questions that need to be answered, AugerPrime was designed. This is an upgrade of the Observatory, which is underway to produce the new Auger Phase II data. AugerPrime includes the installation of new detectors, capable of measuring the muonic component at ground level, and thus help to disentangle the muonic and electromagnetic components of extensive air showers. These new measurements can provide an estimation of the mass composition of cosmic rays at the highest energies, which will help us better understand spectrum features, the origin of UHECRs, and verify the accuracy of hadronic interaction models. In this presentation, we will provide an overview of the AugerPrime design, its current status, performance and potential capabilities of the upgraded Observatory.

Speaker: Dr Nataliia Borodai (Institute of Nuclear Physics, Polish Academy of Sciences)

AugerPrime_TEVPA2024.pdf

37 Proton-air interactions at ultra-high energies in muon-depleted air showers with different depths

The distribution of the number of muons over an ensemble of proton-induced showers at ultra-high energies is shaped by the energy spectrum of secondary neutral pions in cosmic ray-air interactions.
This work finds that the steepness of the muon number distribution in muon-poor showers, quantified by the parameter $\Lambda_\mu$, decreases with the depth of the shower maximum, $X_{\max}$, with increasing dependence on the hadronic interaction model. Additionally, we show that $X_{\max}$ can probe the hadronic activity of the first interaction, so that the evolution of $\Lambda_\mu$ with $X_{\max}$ can be used to constrain the hardness of the energy spectrum of neutral pions in different regions of the kinematic phase-space of the cosmic ray-air interaction.
We verify that an unbiased measurement of $\Lambda_\mu$ is feasible for realistic mass composition expectations. Finally, we check that the statistical precision in $\Lambda_\mu$ required to distinguish between hadronic interaction models can be achieved with current extensive air shower experiments, given their resolution and exposure. Thus, the proposed measurement has the potential to constrain hadronic interactions at center-of-mass energies beyond the reach of human-made colliders.

Speaker: Miguel Alexandre Martins (Instituto Galego de Física de Altas Enerxias)

MAM_LambdaMu_Xmax_TeVPA2024_26082024.pdf

38 Cosmic positrons from catalogued pulsars

We present a new study on the prediction of the cosmic positron flux from catalogued pulsars. The flux is computed on parameters derived from massive simulations performed within several theoretical frameworks. The flux from the Galactic pulsars is then summed to a state-of-the-art prediction on the secondary positron contribution, and compared to AMS-02 data. A synthesis of our analysis is discussed in statistical terms, studying in particular the number of pulsars shaping the measured flux. We finally inspect the properties of the pulsars contributing significantly to the positron flux, and address the multi wavelength and multi-messenger studies desirable to a better understanding of the pulsars’s role in shaping the detected cosmic positron flux.

Speaker: Fiorenza Donato (Torino University & INFN)

TEVPA_Donato.pdf

Parallel Session: Direct Detection

Convener: Leah Jenks (The University of Chicago)

39 Searching for Dark Matter in the French Alps with DAMIC-M

DAMIC-M aims to directly detect DArk MAtter in CCDs in the Laboratoire Souterrain de Modane. By employing fully depleted Charge-Coupled-Devices (CCDs) and a floating gate ("skipper") amplifier, the detector can resolve eV-Scale interactions in the silicon bulk. This unprecedented resolution enables DAMIC-M detector to probe new area of parameter space for Hidden Sector Dark Matter. The DAMIC-M prototype, the Low Background Chamber (LBC), was constructed at the Laboratoire Souterrain de Modane in 2022. The detector features two skipper CCD modules, totally 25g of silicon target mass. The LBC has already achieved a background rate of 6. We will report on the status of the DAMIC-M experiment, the LBC operations, and the results on the search for dark matter – electron scattering.

Speaker: Sravan Munagavalasa (The University of Chicago)

TeVPA_2024_DAMIC_M copy.pdf

40 COSINUS: a new cryogenic dark matter experiment

Today, direct dark matter detection results are contradicting: the DAMA/LIBRA experiment observes an annual modulation signal at high confidence. Furthermore, this signal is perfectly compatible in terms of period and phase with the expectation for a galactic halo of dark matter particles interacting in their NaI target crystals. However, in the so-called standard scenario on dark matter halo and dark matter interaction properties, the DAMA/LIBRA signal contradicts the null results of numerous other experiments. The new experiment COSINUS aims for a model-independent cross-check of the DAMA/LIBRA signal. Such a cross-check has been absent for now and necessarily requires using the same target material (NaI). COSINUS is the only NaI -based experiment operating NaI as a cryogenic detector, which yields several distinctive advantages: discrimination between electronic interactions and nuclear recoils off sodium and iodine on an event-by-event basis, a lower nuclear recoil energy threshold, and a better energy resolution. We finished the construction of the COSINUS experiment at LNGS in 2023; the cryostat is already running at its base temperature of 9mK. In this contribution, we will report on the prototype demonstrator measurement and give an outlook on the few remaining steps towards the start of the data taking in 2025.

Speaker: Florian Reindl (TU Wien)

TeVPA_COSINUS_Reindl_v2.pdf

41 EXCESS events in low-threshold particle detectors

Over the past five years, almost all experiments operating novel sensors with thresholds lower than keV energies have observed large excess rates over expected radioactive backgrounds. These excess rates have been studied in detail over this time, in part through the EXCESS Workshop series. While many of these excess rates share common features, they are not yet fully understood. Moreover, a single common origin is excluded, instead favoring a suite of new background processes unlocked through lower energy thresholds. Multiple efforts are underway to control these excess rates, which will otherwise continue to limit low-threshold detection of dark matter and CEvNS and potentially impact development of reliable quantum computers.

Speaker: Daniel Baxter (Fermi National Accelerator Laboratory)

excess_082624.pdf

42 Measurements of scintillation and ionization signals from low-energy liquid argon nuclear recoils with the ReD experiment

The searches for the signals associated with the interaction of dark matter particles with target material of liquified noble gases have now entered a region of parameter space where nuclear and electronic recoils lead to no more than a few keV of deposited energy. Under those conditions, uncertainties on the response of the medium to the low-energy recoiling particles become crucial to accurately convert the measured scintillation and ionization yields into the total deposited energy. Located at the INFN Sezioni di Catania, Italy, the Recoil Directionality (ReD) experiment has been measuring argon nuclear recoils induced by neutrons in a miniaturized dual-phase time projection chamber (TPC). In this work, we present the results from ReD’s second phase data taking period, during which a final sample of about 820 neutron-induced liquid argon (LAr) nuclear recoils has been selected and its prompt scintillation (S1) and electroluminescence (S2) signals successfully reconstructed as a function of recoil energy. Data versus Monte Carlo comparisons will be presented as well as a preliminary estimate of the S2 gain factor per ionization electron. We also describe ReD’s upcoming third phase, dubbed ReD+, to take place at Laboratori Nazionali del Sud (LNS), Catania, where deuterium-deuterium (DD) reactions will produce a monoenergetic (2.5 MeV) neutron beam with a generator being commissioned at the University of Sao Paulo Physics Institute. ReD+ is expected to operate with mitigated background rates due to enhanced beam collimation by time tagging of the associated 3He particles inside the neutron generator.

Speaker: Edivaldo Moura Santos (University of Sao Paulo)

ReD_DS20k_talk_tevpa_2024_v3.pdf

43 Status of the TESSERACT Dark Matter Experiment

The TESSERACT collaboration will search for dark matter particles below the proton mass through interactions with two types of novel, ultra-sensitive detectors, These detectors, SPICE and HeRALD, aim to provide leading sensitivities to low mass dark matter candidates. The HeRALD experiment will use superfluid He-4 as a target material, which is an ideal kinematic match for dark matter nuclear recoils. SPICE will use different polar crystals with background discrimination to be sensitive to dark photons and other ER and NR signals. Both detectors will be read out by Transition Edge Sensors (TES) that are sensitive to phonon, roton, and light signals from LHe and crystal phonons and photons. In this talk I will be discussing the current R&D progress on SPICE and HeRALD and preliminary simulations of the eventual underground detector.

Speaker: Michael Williams (Lawrence Berkeley National Laboratory)

Status of the TESSERACT Dark Matter Experiment.pdf

Parallel Session: HE Astro / Gravitational Waves

Conveners: Ariane Dekker (The University of Chicago), Dimitrios Kantzas (LAPTh/CNRS)

44 Status of the High Energy cosmic-Radiation Detection (HERD) mission

The High Energy cosmic-Radiation Detection (HERD) facility is a gamma-ray and cosmic-ray telescope planned for installation aboard China's Space Station around 2027. Operating for at least 10 years, HERD aims to precise measure the spectra and composition of charged cosmic rays up to the "knee" region (~few PeVs), monitor the high-energy gamma-ray sky above 100 MeV, and advance the indirect search of dark matter through annihilation or decay processes. HERD is designed as a large acceptance telescope, featuring a central 3D finely segmented calorimeter (CALO), composed of approximately 7500 LYSO crystals. Surrounding the CALO on its top and four lateral faces are three sub-detectors: the scintillating-fiber tracker (FIT) for reconstructing the trajectories of gamma rays and cosmic rays (CRs), the plastic scintillator detector (PSD) to measure the charge of incoming CRs and serve as a veto system for gamma-ray detection, and a silicon charge detector (SCD) for precise measurement of CR charges. Additionally, a transition radiation detector (TRD) is positioned on one lateral side, to provide precise calibration for the CALO in space.
In this presentation, I will present the science goals of the mission and the design and status of current activities. I will highlight the performance of the instrument as accessed through simulations, as well as experimental results on prototype sub-detectors obtained from the recent beam tests campaigns at CERN in Fall 2023. Finally, I will focus on the gamma-ray capabilities of HERD, specifically accessing the design and development of a dedicated trigger based on the combination of FIT signals and PSD veto.

Speaker: Giulio Lucchetta (IFAE-BIST)

Lucchetta_HERD_TeVPA2024.pdf

45 Status of the ALPACA/ALPAQUITA experiment

We started a new air shower observation experiment, ALPACA, to observe cosmic gamma rays and cosmic rays of several TeV or more from the southern sky of the galaxy. The ALPACA’s location is at an altitude of 4,740 m on the hillside in Chacaltaya, Bolivia, The ALPACA consists of a ground-based air shower detector array of 401 scintillation detectors and a large-area water Cherenkov-type underground muon detector array.
For a prototype experiment of the ALPACA, the ALPAQUITA air shower array has been installed and in full operation since 2023. We will report the construction status and initial data analysis of ALPAQUITA.

Speaker: Yusaku katayose (Yokohama national university)

TeVPa2024-ALPAQUITA-katayose.pdf

46 Deployment and Status of the Radar Echo Telescope

The Radar Echo Telescope for Cosmic Rays (RET-CR), a pathfinder experiment for a future ultra-high-energy neutrino detector, is a recently deployed experiment designed to detect the ionization trail from a cosmic-ray-induced particle cascade penetrating a high-altitude ice sheet. In high-elevation ice sheets, a high-energy cosmic ray (E $>$ 10 PeV) at shallow zenith angle deposits more than 10 percent of its primary energy into the ice sheet producing energy densities several orders of magnitude higher than in air. This dense in-ice cascade can then be interrogated with an in-ice radar system. RET-CR consists of a phased-array transmitter and an array of receiving antennas located in the ice, triggered by scintillator panels on the surface with a surface-based radio array to aid in cosmic ray reconstruction. RET-CR is a pathfinder experiment, which aims to test the radar echo method for the Radar Echo Telescope for Neutrinos (RET-N). RET-CR was deployed at Summit Station, Greenland, running from May to August 2024. Initial results from the 2024 deployment will be presented.

Speaker: dylan frikken (Ohio State University)

TEVPA24RETCRTalk.pdf

47 Probing Sterile Neutrinos from Supernova using Gamma ray Telescopes

Core-collapse supernovae (CCSNe) are one of the most energetic particle generators due to their extremely high densities and temperatures. If sterile neutrinos exist, these may also be produced in the supernova core through their mixing with active neutrinos. These heavy sterile neutrinos can escape the stellar envelope and then decay into photons and neutrinos, which can be detected at $\gamma$-ray telescopes and neutrino detectors, respectively. In this talk, I will first revisit the existing gamma ray constraints on the sterile neutrino parameter space from the non-observation of $\gamma$-rays from SN1987A. Finally, I will discuss the sensitivity of several present and near future $\gamma$-ray telescopes assuming a future galactic CCSN.

Speaker: Garv Chauhan (Virginia Tech)

Chauhan_TalkTeVPA(1).pptx

Chauhan_TalkTeVPA.pdf

48 Searching for Beyond-Standard Model Neutrino Physics in Light of AGN Modeling Uncertainties

Identification of high-energy neutrino point sources by IceCube is exciting for particle phenomenology, as propagation of neutrinos over large distances allows us to test properties that are otherwise hard to access. However, many beyond-Standard Model effects would show up as distortions of the energy spectrum, making it difficult to distinguish new physics from uncertainties in the source modeling. In this talk, I will review our recent results using IceCube data to constrain neutrino self-interactions. I will then present recent and ongoing work to determine how well future datasets containing multiple point-source observations could distinguish beyond-Standard Model effects from different Active Galactic Nuclei (AGN) source models.

Speaker: Jeff Hyde (Swarthmore College)

Hyde_TeVPA_2024.pdf

49 Gravitational waves from thick cosmic strings of a supersymmetric flat direction

I will talk about gravitational waves from thick cosmic strings expected in a supersymmetric U(1)_{B-L} extension of the MSSM. The talk would be based on the two paper, JCAP 11 (2023) 016 and JCAP 01 (2024) 015.

Speaker: Wan-il Park (Jeonbuk National University)

Parallel Session: Indirect Detection

Conveners: Deheng Song (Kyoto University), Elena Pinetti (Fermilab)

50 Constraining Dark Matter Annihilation with Fermi -LAT Observations of Ultra-Faint Compact Stellar Systems

Recent observations from optical surveys have discovered the presence of a multitude of ultra-faint compact stellar systems (UFCSs) orbiting the Milky Way (MW) that have the potential to be the most compact and faintest galaxies observed so far. If they were confirmed to be dark matter (DM) dominated, these objects would be ideal for indirect searches of DM annihilation, due to their proximity and relatively high DM content. We analyze 14.3 years of Fermi-LAT gamma-ray data coincident with 26 UFCSs, selected using the results from recent numerical simulations and models of galaxy formation. No excess gamma-ray emission is detected and we evaluate the gamma-ray flux upper limits for these systems. We derive the sensitivity for DM annihilation signal, assuming that these UFCSs are DM-dominated and consistent to the observed population of dwarf spheroidal satellite galaxies (dSphs) of the MW. We also account for the possibility that not all the targets in our sample are DM-dominated, by evaluating the sensitivity for random subsets of the selected UFCSs. This work shows the potential of the UFCSs to yield constraints on DM properties that are competitive with, if not improve, the ones obtained from dSphs, and highlights the importance of kinematic studies on these systems to empirically determine their DM content.

Speaker: Antonio Circiello (Clemson University)

TeVPA_2024.pdf

51 Gamma-ray signals from light dark matter

MeV gamma-ray astronomy will be soon revolutionized by the advent of new telescopes such as COSI, GECCO, and AMEGO-X. In this talk, I will discuss how these telescopes would probe the nature of dark matter (DM) within and beyond the WIMP paradigm. Light DM particles, with masses in the keV-GeV range, would generate gamma rays in the bandpasses of COSI, GECCO, and AMEGO-X through their decay or annihilation into photons, charged leptons, and light mesons such as pions. We consider the phenomenology of light DM in different models involving a new U(1) symmetry, which is common to many well-motivated extensions of the Standard Model of particle physics.

Speaker: Maíra Dutra (NASA Goddard)

MairaDutra_TeVPa.pdf

52 Applying Simulation-Based Inference to Spectral and Spatial Information from the Galactic Center Gamma-Ray Excess

The two most favored explanations of the Fermi Galactic Center gamma-ray
excess (GCE) are millisecond pulsars and self annihilation of the smooth dark matter halo
of the galaxy. In order to distinguish between these possibilities, we would like to optimally
use all information in the available data, including photon direction and energy information.
To date, analyses of the GCE have generally treated directional and energy information
separately, or have ignored one or the other completely. We have developed a method for
analyzing the GCE that relies on simulation-based inference with neural posterior models
to jointly analyze photon directional and spectral information while correctly accounting for
the spatial and energy resolution of the telescope, here assumed to be the Fermi Large Area
Telescope (LAT). These results also have implications for analyses of the diffuse gamma-ray
background.

Speaker: Katharena Christy (University of Hawaiʻi)

TeVPA 2024.pdf

53 Learning the energy dependence of a possible point source explanation of the Galactic Center Excess

An excess of gamma rays from the Galactic center is observed by the Fermi Space Telescope. The two leading hypotheses for the cause of this excess are millisecond pulsars or dark matter. Generically, we expect the statistics of these two sources to differ. We train a convolutional neural network (CNN) to accurately determine the relative flux contribution of point sources to the GCE, training the model on the energy dependent data for the first time. The CNN allows us to avoid biases that have been attributed to existing likelihood based techniques and we show training on energy dependent data produces results that are noticeably dimmer than those obtained by a CNN trained on energy independent data. This suggests there remains even further room for a dark matter contribution to the excess. We validate our results by testing on data simulated with known point source distributions and characterize the effects of mismodeling by testing the CNN on data generated with Galactic background models that differ from the model used to train the CNN.

Speaker: Eve Schoen (UC Berkeley)

tevpa_eve_schoen.pdf

54 Overconfidence in Non-Poissonian Template Fitting

The Non-Poissonian Template Fitting (NPTF) likelihood is widely used for inferring properties of unresolved point sources (PSs) in counts based data, such as those observed by the Fermi Gamma-Ray Space Telescope. I will show that the NPTF likelihood is generically overconfident, i.e. producing narrower confidence intervals / posteriors than expected. I will demonstrate that this effect is primarily due to NPTF not capturing correlations between neighboring pixels caused by PSs under finite point spread functions, and can be understood and corrected in simple cases. For realistic fits that such those concerning the Galactic Center Gamma-Ray Excess, I will argue that NPTF's overconfidence persists, and that Simulation-Based Inference can be a well-calibrated alternative.

Speaker: Yitian Sun (MIT)

YitianSun.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Nepomuk Otte

55 POEMMA Balloon with Radio: a multimessenger approach on an ultra-long duration balloon

The Probe of Extreme Multi-Messenger Astrophysics Balloon with Radio (PBR) is a proposed mission that will fly on a NASA Super pressure Balloon in 2027 from Wanaka, New Zealand. The PBR optical design consists of a 1.1 m aperture Schmidt telescope with a primary mirror of roughly 2m by 2m and a radius of curvature of 1.6m. The hybrid focal surface is made of a fluorescent camera (FC) and a Cherenkov camera (CC). The FC observes Ultra High Energy Cosmic Ray (UHECR, E> 10^18eV)-induced EASs in the ultraviolet (UV) using an array of Multi-Anode Photo-Multiplier Tubes (MAPMTs) imaged every 1 μs; the CC uses a 2048-pixel Silicon Photo-Multiplier (SiPM) imager in a spectral range of 320-900nm with an integration time of 10 ns to observe PeV-airshowers via their Cherenkov emission. In addition, PBR has a Radio Instrument (RI) for the detection of EASs (covering the 50-500 MHz range). PBR has 3 main scientific objectives: to observe UHECRs via the fluorescence technique from suborbital space; to observe horizontal high-altitude air showers (HAHAs) with energies above the cosmic ray knee (E>0.5 PeV) using the optical and radio detection for the first time and to follow astrophysical event alerts in the search of Very High Energy Neutrinos (VHENs E>10^15). This overview will provide a summary of the mission and the current status of PBR.

Speaker: Beatrice Panico (UNINA "Federico II" - INFN Naples)

PANICO_TevPA24.pdf

56 The Radio-Neutrino Observatory in Greenland: Status and Perspectives

High-energy neutrinos propagating over cosmological distances are the ideal messenger particle for astrophysical phenomena, but the neutrino landscape above 10 PeV is currently completely uncharted.
At these extreme energies and the frugal flux expected, the dominant experimental strategy is to detect radiofrequency emissions from particle cascades produced by neutrinos interacting in the vast polar ice sheets.
The Radio Neutrino Observatory in Greenland (RNO-G) is an array of radio antennas embedded in the ice near Summit Station, currently being deployed. At completion, RNO-G will consist of 35 autonomous antenna stations interspaced by 1.25 km on a rectangular grid, making it the largest and most sensitive in-ice neutrino telescope with unique access to the northern sky.
In this talk, I will introduce the RNO-G design and its science goals, outline calibration and analysis strategies developed on the way to first physics, and share a look at the data collected by the first seven operating stations.

Speaker: Philipp Windischhofer (University of Chicago)

2024_08_26_RNOG_overview_noanim.pdf

57 Progress towards an array-wide diffuse UHE neutrino search with the Askaryan Radio Array

The Askaryan Radio Array (ARA) is an in-ice ultrahigh energy (UHE) neutrino experiment at the South Pole. ARA aims to detect the radio emissions from neutrino-induced particle showers using in-ice clusters of antennas buried ~200 m deep on a roughly cubical lattice with side length of ~10 m. ARA has five such independent stations which have collectively accumulated ~30 station-years of livetime. The fifth station of ARA has an additional sub-detector, known as the phased array, which pioneered an interferometric trigger constructed by beamforming the signals of 7 tightly packed, vertically-polarized antennas. This scheme has been demonstrated to significantly improve the trigger efficiency for low SNR signals. In this talk, we will present the current state of the first array-wide diffuse neutrino search using 25 station-years of data. We anticipate that this analysis will result in the first UHE neutrino observation or world-leading limits from a radio neutrino detector below 1000 EeV. Additionally, this analysis will demonstrate the feasibility for multi-station in-ice radio arrays to successfully conduct an array-wide neutrino search — paving the way for future, large detector arrays such as RNO-G and IceCube-Gen2 Radio.

Speaker: Marco Muzio (Pennsylvania State University)

TeVPA24_Muzio.pdf

58 EUSO-SPB2’s Neutrino Target-of-Opportunity Observation Program and Prospects for PBR

Astrophysical cosmic-ray accelerators capable of reaching ultra-high energies (UHEs) may produce very-high energy (VHE) neutrinos due to interactions of the cosmic rays within their sources or their surrounding environments. Suborbital and space-based optical Cherenkov detectors search for upward-moving extensive air showers generated by decaying tau-leptons produced by the interactions of >~ 10 PeV cosmic tau neutrinos within the Earth. The Extreme Universe Space Observatory on a Super Pressure Balloon II mission (EUSO-SPB2) was a balloon-borne mission to observe the fluorescence and optical Cherenkov signals of extensive air showers generated by cosmic rays and neutrinos. It launched from Wanaka, New Zealand on May 13, 2023 with a flight duration of 1 day, 12 hours, and 53 minutes. In this talk, we discuss the Target-of-Opportunity observation program of EUSO-SPB2 and set the stage for the upcoming flight of the POEMMA-Balloon with Radio (PBR) mission (launch planned in 2027).

Speaker: Tonia Venters (NASA Goddard Space Flight Center)

SPB2_PBR_ToO.pdf

59 Characterization of the Diffuse Astrophysical Neutrino Spectrum with All Flavor Starting Events in IceCube

The IceCube Neutrino Observatory is a neutrino detector at the South Pole, which uses the Cherenkov radiation emitted by charged secondaries from neutrino-nucleon interactions in the ice to reconstruct neutrino events. Events where this interaction vertex is contained inside the detector volume are termed “starting events”. At energies ranging from 1 TeV to 100 TeV, starting event samples are dominated by background from atmospheric muons and neutrinos, necessitating specialized veto techniques for suppression.
We present the Medium Energy Starting Events (MESE) selection, which employs these improved methods to measure the flux of diffuse extragalactic neutrinos down to 1 TeV from the entire sky. We will present a measurement of the spectrum of the diffuse flux of neutrinos, which demonstrates strong evidence for structure beyond a single power law.

Speaker: Vedant Basu (Wisconsin IceCube Particle Astrophysics Center)

TEVPA_MESE_Diffuse.pdf

60 BSM Physics with IceCube Tracks: Sterile Neutrinos and More

The IceCube Neutrino Observatory is a neutrino telescope built into the ice at the South Pole. IceCube observes “tracks” produced by charged current (CC) interactions from astrophysical and atmospheric muon neutrinos. Unlike “cascades” from electron neutrino CC, and other neutral current interactions, the energy resolution of tracks is limited by the track length contained within the detector. Due to recent machine-learning-based advances in reconstruction, the precision of the neutrino energy reconstruction for TeV-scale track-like events has improved significantly. This opens up a wide variety of searches for Beyond the Standard Model Physics, including improved searches for a sterile neutrino and studies of the flavor composition of Galactic neutrinos. Current analyses and recent results related to these searches are discussed.

Speaker: John Hardin (MIT)

BSM Physics with IceCube Tracks_ Sterile Neutrinos and More_submit.pdf

5:45 PM Reception

Tuesday, August 27

Registration: Breakfast

Plenary Session

61 Searching for new physics at cosmic dawn

I will describe how the cosmic-dawn era, which saw the formation of the first galaxies, holds a wealth of information about dark matter and new physics in the early universe. The next decade will see detailed maps of this era with both 21-cm and space telescopes like the new James Webb. I will show how to use the upcoming data to measure dark-matter structure formation at smaller scales—and earlier times—than ever before. I will also describe how, intriguingly, the first JWST observations appear to be in tension with our models, perhaps pointing at new physics at high redshifts.

Speaker: Julian Munoz

TeVPA_cosmicdawnNewPhys.pdf

62 Dark matter interactions: from the early universe to near-field cosmology

Cosmological observables, from the CMB anisotropy to the census of galaxies in the local universe, offer the most direct and broad tests for the nature of dark matter, including a number of scenarios that involve dark matter interactions, often challenging or even impossible to test in a laboratory setting. I will review the status of the recent early-universe and late-universe searches for the identity of dark matter, summarizing the best current limits on scattering between dark matter and baryons, the non-thermal production mechanisms for sterile neutrinos, and mass bounds on thermal-relic dark matter. I will highlight the interplay between complementary probes of dark matter physics and discuss the prospects for unveiling the physics of dark matter in the coming decade.

Speaker: Vera Gluscevic (USC)

63 Galaxies as Probes of the Particle Physics Nature of Dark Matter

The hypothesis of Cold Dark Matter (CDM) has been spectacularly confirmed on the largest scales of the Universe and must now be stress-tested on sub-galactic scales. Many well-motivated and generic alternatives to CDM can leave spectacular signatures on precisely these scales, affecting the evolution of galaxies as well as their population statistics. Excitingly, over the course of the next decade, a flood of astrophysical data will open the possibility of searching for these distinctive imprints and shedding light on key questions about dark matter. I will review the promise of upcoming data as well as recent theory advancements for modeling dark matter physics on these scales.

Speaker: Mariangela Lisanti (Princeton University)

Lisanti_TeVPa.pdf

10:30 AM Coffee break

Plenary Session

64 Preparing simulations for the precision era of dark matter cosmology

We are in an era of unprecedented volumes of astronomical data that can elucidate the nature and properties of dark matter—if we have predictions that are well-matched to the precision of the data sets. In this talk, I will highlight a sample of the triumphs and challenges in using simulations to predict cosmic phenomenal for different dark matter models.

Speaker: Annika Peter (OSU)

peter_tevpa2024.pdf

65 The Science Potential of the Cherenkov Telescope Array Observatory

The Cherenkov Telescope Array Observatory (CTAO) is the upcoming next-generation ground-based gamma-ray observatory. The CTAO will achieve superior sensitivity, angular, and spectral resolution over a broader energy range (tens of GeV to hundreds of TeV) compared to currently operating imaging air Cherenkov telescopes (IACTs). Full-sky coverage will be achieved with two IACT arrays in the northern and southern hemisphere, featuring three different telescope sizes. The CTAO will address a plethora of science questions including how particles are accelerated in extreme environments and what is the nature of dark matter (and in general the search for physics beyond the Standard Model). This talk will outline this broad science potential and provide the current status and timeline of the CTAO.

Speaker: Manuel Meyer (University of Southern Denmark)

CTA-overview-mmeyer.pdf

12:10 PM Lunch

Parallel Session: Cosmic Rays

Conveners: Benedikt Schroer (The University of Chicago), Rebecca Diesing (Institute for Advanced Study and Columbia University), Toshihiro Fujii (Osaka Metropolitan University)

66 Astroparticle Fill-In-The-Blank: Using Atmospheric Muons to Study Tornadoes

Tornadoes are severe weather phenomena characterized by a violently rotating column of air connecting the ground to a parent storm. Within the United States, hundreds of tornadoes occur every year. Despite this, the dynamics of tornado formation and propagation are not particularly well understood, in part due to the challenge of instrumentation. Many existing instruments are in-situ detectors, making deployment in or near an active or developing tornado difficult. Atmospheric muons may present a partial solution to this problem, as their flux has been shown to be affected by local atmospheric conditions, allowing for measurements of atmospheric parameters at a range. While this technique has been used in the past on larger, more stable weather systems, tornadic supercells present a unique challenge due to their transience and relatively small size. This talk explores prospects for remote measurement of the pressure field surrounding tornadic supercells by combining simulation of supercell thunderstorms and cosmic ray showers to quantify the local effect of these storms on the atmospheric muon flux.

Speaker: William Luszczak (Ohio State University)

TevPA_2024_tornadoes.pdf

67 Space weather monitoring and forecasting: a data-driven approach

Space infrastructures increasingly need highly efficient monitoring systems that detect rare and energetic events. Deep learning pipelines are one of the most promising and innovative approaches towards the development of such systems. However, leveraging machine learning to detect or predict rare events requires careful data preparation, as the training process significantly impacts the performance of the neural network architecture.
To illustrate the intricacies of this approach, we will consider the example of forecasting geomagnetic storms using data that includes typical quantities collected by satellites like the China Seismo-Electromagnetic Satellite (CSES). The CSES has proven its ability to observe various space weather phenomena, including solar energetic particle events, solar flares, and geomagnetic storms. The CSES captures a wide range of data through a multi-payload approach, including energetic particles spanning three orders of magnitude, electromagnetic fields, and plasma density. Soon to expand into a constellation of two satellites, CSES will become a powerful resource for observational astrophysics.
We will show that the strategy proposed for creating datasets for training and validation plays a fundamental role in guaranteeing the capability of giving correct forecasting of stormy and disturbed geomagnetic periods.

Speaker: Marco Cristoforetti

TeVPA2024_cristoforetti.pdf

68 Gamma-Ray and AntiMatter Survey(GRAMS) Experiment

The Gamma-Ray and AntiMatter Survey (GRAMS) is a next-generation experiment using a Liquid Argon Time Projection Chamber (LArTPC) detector to detect gamma rays and antiparticles. Gamma-ray surveys are important for understanding multi-messenger and time-domain astronomy, enabling exploration of the universe's most potent events, such as supernovae and neutron star mergers etc. Despite the significance of MeV gamma-rays, GRAMS could also explore the so-called 'MeV gap' region to improve MeV gamma-ray measurement sensitivity that was restricted by the hardness of accurately reconstructing Compton events. Aside from gamma-ray detection, the GRAMS proposed method also serves as an antiparticle spectrometer, targeting low-energy range cosmic-ray measurement. This talk will provide updates on the current status and progress toward the first prototype balloon flight with a small-scale LArTPC (pGRAMS) scheduled for 2025/2026.

Speaker: Tsuguo Aramaki (Northeastern University)

TeVPA2024_GRAMS_TsuguoAramaki.pdf

69 Latest advancements on the cosmic-ray proton flux towards PeV energies with DAMPE

The DArk Matter Particle Explorer (DAMPE) is a satellite-borne experiment, in operation since 2015, aimed at studying high-energy cosmic rays and gammas. Protons are the most abundant element in cosmic rays. Given their smaller interaction cross-sections with the interstellar medium (compared to heavier nuclei), they can travel larger distances, thereby becoming important probes to cosmic-ray sources as well as acceleration and propagation mechanisms. Recently, in the DAMPE collaboration, machine learning (ML) techniques were developed and deployed to improve particle tracking and identification as well as compensate for the energy lost in the calorimeter at high energies due to the saturation of the electronics. This work presents an updated measurement of the energy spectrum of cosmic-ray protons, introducing the application of the above-mentioned ML techniques, thus leading to an extension at higher energies.

Speaker: Andrii Tykhonov (University of Geneva)

TEVPA2024_DAMPE_Tykhonov-min.pdf

70 Evaluating the potential of low mass stars as sources of TeV cosmic rays

Most stars are M dwarfs, many of which possess kilogauss magnetic fields. For the subset of those with fields arranged into strongly dipolar magnetospheres, the simplest application of the Hillas criterion suggests that these magnetospheres could trap protons with energies up to 20 PeV, and a more cautious estimate puts the limit at tens of TeV. This presentation explores the prospects for M dwarfs as sources of TeV particles. I assess whether particle acceleration processes previously discussed for other objects with dipolar magnetospheres—from planets to pulsars-–should be considered for M dwarfs. I also present preliminary results from a search for gamma ray emission with Fermi data for the nearby M dwarf UV Ceti. Previous searches for gamma ray emission from M dwarfs have not considered the importance of focusing on those with dipolar magnetospheres. Radio emission from UV Ceti includes auroral activity, indicative of particle acceleration in large-scale current systems in the dipolar magnetosphere, and I include recent observations of this star with the Very Large Array.

Speaker: Kathryn Plant (NASA JPL/ Caltech)

Parallel Session: Dark Matter

Conveners: Gordan Krnjaic (The University of Chicago), Pouya Asadi (University of Oregon)

71 Scalars remember the hot big bang

Fifth force and equivalence principle tests search for new physics by precisely measuring forces between macroscopic objects and their properties under free fall. These experiments test the interactions between macroscopic collections of atoms and molecules, and any new interactions effectively take place between these low energy degrees of freedom.
In contrast, the early Universe plasma probes these interactions at a more fundamental level.
In this talk, I will consider the case of a scalar mediating a fifth force, and show that the effects of dimensional transmutation, spontaneous symmetry breaking, and the running of the gauge couplings cause the scalar interactions to mix, leading to nearly universal dynamics at early times. Using the well-known expressions for the pressure of the Standard Model during its various epochs to compute the scalar effective potential, I will show that scalar couplings to matter larger than $\sim 10^{-6}(m_\phi/\eV)^{-1/4}$ relative to gravity produce the correct dark matter abundance, motivating new physics searches in this part of parameter space.

Speaker: David Cyncynates (University of Washington, Seattle)

TeVPA.pdf

72 Detecting Rare Species of Dark Matter with Terrestrial Detectors

A sub-component of dark matter with a short collision length compared to a planetary size leads to efficient accumulation of dark matter in astrophysical bodies. Such particles represent an interesting physics target since they can evade existing bounds from direct detection due to their rapid thermalization in high-density environments. In this talk, I will demonstrate that terrestrial probes, such as, large-volume neutrino telescopes as well as commercial/research nuclear reactors, can provide novel ways to constrain or discover such particles.

Speaker: Anupam Ray (UC Berkeley)

TeVPA_Anupam.pdf

73 Searching for Dark Photon Production Using Genetic Algorithms

Dark matter has been a key area of research in physics for over ninety years. The dark photon is a proposed model of dark matter that extends the Standard Model to add a new force mediator to interact with the dark sector. The focus of this paper was to investigate the plausibility of using modern computational techniques, most prominently genetic algorithms, to simulate and detect production of dark photons via meson decay. To simulate dark photon production, the Pythia8.3 library was used to create a dataset of 500,000 points. Then, a genetic algorithm was used to find an optimized AdaBoost model with the highest accuracy on the dataset. The algorithm changed the number of estimators and the learning rate for the model and assigned a fitness based on the accuracy on the testing dataset. The optimized AdaBoost model was evaluated to have a 99.995% accuracy on the testing dataset, with 80% accuracy on instances where a dark photon was produced. These statistics make genetic algorithms a viable solution to optimize decision tree models in the field of particle physics.

Speaker: Rohan Arni (High Technology High School)

ArniRohan-TeVPA.pdf

74 Dark Matter Raining on DUNE and Other Large Volume Detectors

Long-range forces in the dark sector can modify possible detection signatures of dark matter (DM). In this talk, I will discuss the scenario whereby 100% of the DM passing through the Earth is boosted due to new attractive long-range forces. This results in two main improvements in detection capabilities: 1) the large boost allows for detectable signatures of DM well below a GeV at large-volume neutrino detectors, such as DUNE, Super-K, Hyper-K, and JUNO, as possible DM detectors, and 2) the flux at the Earth’s surface is enhanced by a focusing effect. In particular, the latter also leads to a significant anisotropy in the signal, with the DM flux being predominantly vertical at the Earth’s surface. I will show the prospective sensitivity of the above experiments to this scenario, and discuss the implications for different models with long-range forces.

Speaker: Javier Acevedo (SLAC)

TevPA2024_JFA.pdf

75 Loosely Bound Composite Dark Matter

In this talk, we discuss loosely bound composite states of dark matter, where the binding energy per constituent particle is much lower than the constituent’s bare mass. In particular, we investigate the direct detection signatures of nuclear and molecular dark matter, in which constituents are separated by scales much larger than the inverse constituent mass. We find that these composites can have a very large scattering cross-section with Standard Model nuclei, scaling with nucleon number as $\sim A^4$. Furthermore, for some couplings, these composites produce sub-eV individual atomic recoils, while still depositing a large total amount of energy in a single passage through a detector. This implies an interesting new class of signatures for low-threshold direct detection.

Speaker: Yilda Boukhtouchen (Queen's University)

TEVPA2024_CompositeDM_V3.pdf

76 A ROMP through Dark Matter in the early universe

The microphysical properties of Dark Matter (DM), such as its mass and coupling strength, are typically assumed to retain their vacuum values for any given model when considering DM behaviour at a range of scales. However, DM interactions in different astrophysical and cosmological environments are impacted by the properties of the background which in turn can substantially affect both DM production and its detection prospects.. This is particularly true for models where a mixing between DM and another field gives rise to oscillations, such as in the case of sterile neutrinos, dark photons and axions.

In this talk, I will provide an overview of some of these effects when DM is a ROMP ('Rapidly Oscillating Massive Particle'). I will detail a general framework for calculating DM abundance in such a setup, in the presence and absence of a resonance and accounting for the impact of the cosmological plasma. I will discuss the viable parameter space for such a production mechanism and the associated phenomenology.

Speaker: Saniya Heeba (McGill University)

TeVPa_ROMPs.pdf

Parallel Session: Gamma ray astronomy

Conveners: Anastasia Sokolenko, Mahmoud S A Alawashra (DESY)

77 Gamma-ray Emission from a Young Star Cluster in the Star-Forming Region RCW 38

Speaker: Paarmita Pandey (The Ohio State University)

Pandey_TEVPA.pdf

78 Temporal variability and SED evolution modeling of Mrk421 during its most violent year

Speaker: Jayant Abhir (ETH Zurich)

TeVPA 2024 Mrk421 2010 campaign v6.pdf

79 Constraints on the intergalactic magnetic field from Fermi-LAT observations of GRB 221009A

Speaker: Manuel Meyer (University of Southern Denmark)

Meyer_IGMF_GRB2210009A.pdf

80 Modeling the Afterglow of GRB 221009A: Constraints from MeV-GeV-TeV Data

Speaker: Luca Foffano (INAF)

LucaFoffano_TeVPA2024_GRB221009A_270824_upload_new.pdf

81 HESS J1809-193 : Gamma Ray emission by Cosmic Ray from the Past Explosion

Speaker: Sovan Boxi (Raman Research Institute)

82 A real-time monitoring on extragalatic tranisents with the LHAASO-WCDA detector

Speaker: Min ZHA

20240827_lhaaso_realtime.pdf

Parallel Session: Indirect Detection

Conveners: Elena Pinetti (Fermilab), Weishuang Linda Xu (UC Berkeley/LBNL)

83 Birth of the first stars amidst decaying and annihilating dark matter

The first stars are expected to form through molecular-hydrogen (H$_2$) cooling, a channel that is especially sensitive to the thermal and ionization state of gas, and can thus act as a probe of exotic energy injection from decaying or annihilating dark matter (DM). I will discuss using a toy halo model to study the impact of DM-sourced energy injection on the H$_2$ content of the first galaxies, and thus estimate the threshold mass required for a halo to form stars at high redshifts. I will show that currently allowed DM models can significantly change this threshold, producing both positive and negative feedback and estimate how this can impact the timing of 21cm signals at cosmic dawn.

Speaker: Wenzer Qin (New York University)

2024-08-27 TeVPA.pdf

84 Seeking pulsars for dark matter scattering searches

The heating of an old neutron star (NS) due to dark matter annihilation and kinetic heating provides a compelling avenue for dark matter detection. This process can significantly elevate the temperature of the NS, potentially making it observable as a black body with telescopes like the E-ELT or TMT, particularly for those NSs in close proximity. Given that the majority of NSs have been identified as pulsars, these represent a critical class of nearby candidates for observing dark matter heating. I will discuss the challenges and methods involved in identifying the closest pulsar by revising the electron column density map for the region near Earth.

Speaker: Narayani Tyagi (Queen's University)

TeVPA 2024 Closest Pulsars Talk.pdf

85 Immortal Stars at the Galactic Center

Dark matter can be captured in stars and annihilate, providing the star with a new energy source in addition to nuclear fusion. This significantly changes stellar evolution at the Galactic Center, where the dark matter density is extremely high. As dark matter burning replaces nuclear fusion partially or completely, stars become longer-lived, as they use up hydrogen more conservatively, or even become immortal, as dark matter is re-supplied continuously. We show that this results in several prominent features that distinguish stellar populations in dark matter dense environments from populations without dark matter. This may offer an explanation for the unusually young stars at the Galactic Center, called the paradox of youth, as well as their top-heavy mass distribution. In some scenarios, the dark matter annihilation power can become so intense to disrupt star formation entirely, allowing us to derive constraints on dark matter-nucleon cross sections and density profiles based on stellar observations close to the Galactic Center.

Speaker: Isabelle John (Stockholm University)

TeVPA_Chicago_2024.pdf

86 Dark Kinetic Heating of Exoplanets and Brown Dwarfs

Dark kinetic heating of neutron stars has been previously studied as a promising dark matter detection avenue. Kinetic heating occurs when dark matter is sped up to relativistic speeds in the gravitational well of high-escape velocity objects, and deposits kinetic energy after becoming captured by the object, thereby increasing its temperature. We show that dark kinetic heating can be significant even in objects with low-escape velocities, such as exoplanets and brown dwarfs, increasing the discovery potential of such searches. This can occur if there is a long-range dark force, creating a "dark escape velocity", leading to heating rates substantially larger than those expected from neutron stars. We consequently set constraints on dark sector parameters using Wide-field Infrared Survey Explorer and JWST data on Super-Jupiter WISE 0855-0714, and map out future sensitivity to the dark matter scattering cross section below $10^{-40}~$cm$^2$. We compare dark kinetic heating rates of other lower escape velocity objects such as the Earth, Sun, and white dwarfs, finding complementary kinetic heating signals are possible depending on particle physics parameters.

Speaker: Aidan Reilly (Stanford University)

TevPA 2024 public.pdf

87 Dark matter limits from the tip of the red giant branch

Capture and annihilation of WIMP-like dark matter in red giant stars can lead to faster-than-expected ignition of the helium core, and thus a lower tip of the red giant branch (TRGB) luminosity. We use Gaia data to place constraints on the dark matter-nucleon cross section using TRGB of 22 globular clusters with measured TRGB luminosities, and place projections on the sensitivity resulting from 161 clusters with full phase space distributions observed by Gaia. Although limits remain orders of magnitude weaker than those from Earth-based direct detection experiments, they represent a constraint that is fully independent of dark matter properties in the Solar neighbourhood, probing its properties across the entire Milky Way galaxy.

Speaker: Aaron Vincent (Queen's University)

TeVPA globulars.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Tianlu Yuan (UW Madison)

88 IceCube searches for neutrinos from gravitational wave sources

The IceCube Neutrino Observatory is sensitive to the full sky, with nearly 100% up time. It is therefore well suited to search for neutrinos accompanying transient sources, including the sources of gravitational waves. Various models predict that neutrinos could be produced by compact object mergers including at least one neutron star or even by binary black hole mergers. For every gravitational wave event detected by LIGO/Virgo/KAGRA, we have searched for accompanying neutrinos coincident in time and direction, using multiple neutrino event signatures, energy ranges, and analysis methods. This includes low-threshold real-time searches in order to rapidly inform other observers of a possible coincident neutrino, which is typically localized hundreds of times more precisely than a gravitational wave. During the ongoing observing run O4, we publish results of the neutrino searches with a median latency of 21 minutes from the gravitational wave’s arrival at Earth. I will summarize our previous searches as well as results to date during O4.

Speaker: Justin Vandenbroucke (University of Wisconsin – Madison)

vandenbroucke_240827_tevpa_icecube_gw_v2.pdf

vandenbroucke_240827_tevpa_icecube_gw_v2.pptx

89 Characterizing High-Energy Neutrino Emission Parameters in Bright Seyfert Galaxies and Quasars

Observation of high-energy neutrinos from the direction of nearby active galaxy, NGC 1068, was a major step in identifying for the origin of high-energy neutrinos. This observation revealed that high-energy neutrinos originated at the heart of active galaxies which are opaque to gamma-ray emission. The realization that is reinforced by the excess of neutrinos in the direction of NGC 4151, another nearby AGN. Modeling neutrino emission from the core of AGN relies on the multi-wavelength observation of the inner parts of the active galaxy and is challenging due to the uncertainties associated with the absorption of emission in these dense environments. Here, we employ the measured neutrino spectra together with the sub-GeV gamma-ray emission measured by the Fermi satellite to break the degeneracy and narrow in on the parameter space of neutrino emission from the coronae of AGN. Our result will help estimating the prospects for identification of additional sources and guide future targeted analyses

Speaker: Jose Carpio (University of Nevada Las Vegas)

TeVPA_Carpio.pdf

90 Search for neutrino emission from Seyfert Galaxies with IceCube

The IceCube Neutrino Observatory has reported evidence of TeV-scale neutrinos emitted from NGC 1068, a nearby Seyfert II galaxy. The evidence suggests that active galactic nuclei could be potential sources of high-energy astrophysical neutrinos. The absence of the expected accompanying flux of TeV gamma-rays indicates that they could have been efficiently obscured at their production site, where the hot coronal environment near the core of the Seyfert Galaxy naturally becomes a candidate. According to theoretical models, the property of the corona, and therefore the production of neutrinos, can be calculated by using the intrinsic X-ray luminosity. In this poster, we present our search for neutrino emission from a sample of intrinsic X-ray bright Seyfert Galaxies selected from the BASS survey. In our study, we employed a disc-corona model of the neutrino flux to improve the discovery potential of the search and compared it to using the standard power-law flux assumption.

Speaker: Shiqi Yu (university of utah)

TeVPA2024_ Seyfert.pdf

91 Search for Astrophysical Neutrinos from 4FGL Galactic Plane Sources with the Pion Bump Signature

The IceCube Neutrino Observatory is a neutrino detector located at the South Pole, comprising a cubic-kilometer volume within the Antarctic ice. IceCube has recently observed a diffuse flux of neutrinos from the Galactic Plane. However, no individual point source of astrophysical neutrinos from the Milky Way have been detected yet. Hadronic gamma rays produced through the decay of neutral pions result in a distinctive "pion-bump" or "spectral break" around energies of 200 MeV. A total of 56 sources in the 4FGL catalog by Fermi-LAT Collaboration have shown evidence for this spectral break signature. Detecting astrophysical neutrinos from these sources would provide further evidence of cosmic-ray acceleration in the vicinity of the sources. In this work, we will present a dedicated analysis of the 56 4FGL sources with a pion bump signature to look for astrophysical neutrinos using 13 years of IceCube data. We show that the analysis could advance our knowledge of potentially new acceleration sites and provide a direct probe of CR acceleration in the galaxy.

Speaker: Rishi Babu (Michigan State University)

[IceCube]TeVPA-2.pdf

Parallel Session: Particle Physics/Cosmology

Conveners: Huangyu Xiao (KICP and Fermilab), Nicholas Kamp (Harvard University)

92 Primordial black hole probes of heavy neutral leptons

Primordial black holes (PBH), while still constituting a viable dark matter component, are expected to evaporate through Hawking radiation.
Assuming the semi-classical approximation holds up to near the Planck scale, PBHs are expected to evaporate by the present time, emitting a significant flux of particles in their final moments, if produced in the early Universe with an initial mass of $\sim 10^{15}$ g.
These ``exploding'' black holes will release a burst of Standard Model particles alongside any additional degrees of freedom, should they exist.
We explore the possibility that heavy neutral leptons (HNL), mixing with active neutrinos, are emitted in the final evaporation stages.
We calculate the expected number of active neutrinos from such an event, including contributions due to the HNL decay for different assumptions on the mixings.
We infer sensitivities on the active-sterile neutrino mixing and on the sterile neutrino mass, finding that, for instance, for the scenario where $U_{\tau 4}\neq 0$, IceCube could improve current constraints by $\sim 2$ orders of magnitude, for HNLs masses between 0.1 - 1 GeV, for a PBH at a distance of $\sim 10^{-4}$ pc from Earth.

Speaker: Agnese Tolino (IFIC (CSIC-UV))

Tolino_TeVPA.pdf

93 Leptogenesis, dark matter and gravitational waves from discrete symmetry breaking

We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator $\Phi$, stabilised by a discrete $Z_4$​ symmetry that breaks to a remnant $Z_2​$ upon $\Phi$ acquiring a non-zerovacuum expectation value ($v_\phi$). The model accounts for the observed baryon asymmetry of the universe via additional contributions to the canonical Type-I leptogenesis. The $Z_4$​ symmetry breaking scale ($v_\phi$) in the model not only establishes a connection between the neutrino sector and the dark sector, but could also lead to gravitational wave signals that are within the reach of current and future experimental sensitivities.

Speaker: Drona Vatsyayan (IFIC, Universitat de Valencia)

Drona_TeVPA24.pdf

94 Boosted Relic Neutrino Background by Cosmic Reservoirs

The detection of the relic neutrino background (RννB) is the "Holy Grail" of neutrino physics and it is extremely challenging due to the tiny cross sections of the relic neutrinos.
A possible way-out is looking for signatures of the highest-energy scatterings that the RνB undergo in the Universe, to maximise their SM cross sections
We compute the flux of relic neutrino background (RννB) up-scattered by ultra-high-energy cosmic rays (UHECRs) in clusters that act as CR-reservoirs. The long trapping times of UHECRs in clusters make this flux larger than RννB up-scattered by UHECRs on their way to Earth. We find that IceCube excludes RννB weighted overdensities larger than $10^{10}$ in clusters, and that planned experiments such as PUEO, RNO-G, GRAND and IceCube-Gen2 will be sensitive to values down to $10^{8}$.
Our analysis includes the momentum transfer dependence of the neutrino-nucleus cross section, deep inelastic scattering, a mixed UHECR composition, and flavour information on the up-scattered RννB fluxes, providing new ways to possibly disentangle the up-scattered RννB from cosmogenic neutrinos.

Speaker: Jacopo Nava

JacopoNava_TeVPA_2024.pdf

95 Neutrino mass bounds from DESI 2024 are relaxed by Planck PR4 and cosmological supernovae

The recent DESI 2024 Baryon Acoustic Oscillations (BAO) measurements combined with the CMB data from the Planck 18 PR3 dataset and the Planck PR4+ACT DR6 lensing data, with a prior on the sum of the neutrino masses $\sum m_\nu>0$, leads to a strong constraint, $\sum m_\nu<0.072$ eV, which would exclude the inverted neutrino hierarchy and put some tension on even the standard hierarchy. We show that actually this bound gets significantly relaxed when combining the new DESI measurements with the Hillipop + Lollipop likelihoods, based on the Planck 2020 PR4 dataset, and with supernovae datasets. We note that the fact that neutrino masses are pushed towards zero, and even towards negative values, is known to be correlated with the so-called $A_L$ tension, a mismatch between lensing and power spectrum measurements in the Planck PR3 data, which is reduced by Hillipop + Lollipop to less than 1$\sigma$. We find $\sum m_\nu<0.1$ eV and $\sum m_\nu<0.12$ eV, with the supernovae Pantheon+ and DES-SN5YR datasets respectively. The shift caused by these datasets is more compatible with the expectations from neutrino oscillation experiments, and both the normal and inverted hierarchy scenarios remain now viable, even with the $\sum m_\nu>0$ prior. Finally, we analyze neutrino mass bounds in an extension of $\Lambda$CDM that addresses the $H_0$ tension, with extra fluid Dark Radiation, finding that in such models bounds are further relaxed and the posterior probability for $\sum m_\nu$ begins to exhibit a peak at positive values.

Speaker: Itamar Allali (Brown University)

IJA_TevPA_24.pdf

96 CUPID: The next generation upgrade of CUORE to search for 0νββ decay

The search for neutrinoless double beta (0$\nu\beta\beta$) decay is ongoing and aims to determine whether the neutrino is Majorana in nature. Discovery of such a process would immediately imply lepton number violation and represent new physics beyond the standard model. This search has been ongoing for a few decades with multiple experimental strategies and choices of isotope. CUPID (CUORE Upgrade with Particle ID) is a next generation experiment searching for 0$\nu\beta\beta$ decay in $^{100}$Mo using enriched scintillating lithium molybdate (LMO) crystals and profiting from several years of experience gained with its predecessor, CUORE (Cryogenic Underground Observatory for Rare Events). CUPID will consist of 1596 LMO crystals operated as bolometers, coupled to 1710 light detectors allowing for the simultaneous readout of both heat and light energy. This strategy allows for the rejection of $\alpha$ events, a dominant source of background in CUORE, by exploiting the different ratio of heat to light energy for $\beta/\gamma$ induced events compared to $\alpha$ events. With this CUPID can reach a sensitivity greater than $1x10^{27}$ yr. Currently ongoing studies, simulations, and R&D projects are all working towards the finalization of the CUPID detector design and to assess its performance and physics reach. In this presentation we will provide an overview of the CUPID program and highlight upcoming milestones towards the construction of the experiment.

Speaker: Bradford Welliver (UC Berkeley)

cupid_tevpa2024_bwelliver.pdf

3:30 PM Coffee break

Parallel Session: Cosmic Rays

Conveners: Andrii Tykhonov (University of Geneva), Benedikt Schroer (The University of Chicago), Fiorenza Donato (Torino University & INFN)

97 Scrutinising cosmic ray accelerators with spectral features

Cosmic ray measurements have reached a remarkable level of precision in recent years. The nature of cosmic ray sources, however, remains elusive. Our limited knowledge about the source properties and positions poses a challenge for predictions of cosmic ray fluxes in our Galaxy. Thus, it is a common model assumption that cosmic rays are injected by a smooth and steady source continuum. However, supernova remnants, the likely sources of Galactic cosmic rays, are point-like on Galactic scales and inject cosmic rays for a finite period of time. This renders predictions of the cosmic ray fluxes very sensitive to the sources’ positions and injection properties. As these parameters are not accessible through observations directly, the source modelling must be done probabilistically. We present results of Monte Carlo simulations of the cosmic ray proton flux and discuss how precision measurements by current experiments like AMS-02 and DAMPE, as well as potential future experiments like AMS-100 can be used to constrain the energy dependence of escape from the cosmic ray accelerators. Gaining additional insights about cosmic ray sources is crucial for better theoretical predictions of the cosmic ray distribution and, by implication, gamma-ray and neutrino distributions in the Galaxy, too.

Speaker: Anton Stall (Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University)

TeVPa_2024_Anton_Stall.pdf

98 Particle Acceleration by Magnetized Turbulence in Coronae of Active Galactic Nuclei

The cores of active galactic nuclei (AGN) are potential accelerators of 10-100 TeV cosmic rays, which in turn can produce high-energy neutrinos. This hypothesis has been supported by compelling evidence of a TeV neutrino signal from the nearby active galaxy NGC 1068. However, the specific site and mechanism of cosmic ray acceleration remain open questions. One promising candidate is magnetized turbulence in the corona of the central supermassive black hole. Using first-principles fully kinetic (PIC) simulations, we demonstrate that the accelerated particles are extracted from the thermal pool in magnetic reconnection layers that form self-consistently within the turbulent cascade. These injected particles are then stochastically accelerated via non-resonant interactions with large-scale turbulent fluctuations. We characterize the stochastic acceleration process using an effective diffusion coefficient in momentum space that we derive directly from the PIC simulations. We apply our first-principles simulation results to investigate cosmic ray acceleration in the corona of NGC 1068, showing that when the turbulent magnetic energy density exceeds 1% of the rest mass energy density, proton acceleration by magnetized turbulence can naturally account for the observed IceCube neutrino signal from NGC 1068.

Speaker: Luca Comisso (Columbia University)

Comisso_TeVPA_2024.pdf

99 Particle acceleration in 3D hybrid simulations of astrophysical quasi-perpendicular shocks

Understanding the conditions conducive to particle acceleration at collisionless, non-relativistic shocks, like those of supernova remnants, is important to unveil the origin of cosmic rays. We use hybrid (kinetic ions—fluid electrons) kinetic simulations to investigate particle acceleration and magnetic field amplification at non-relativistic, weakly magnetized, quasi-perpendicular shocks. So far, no self-consistent kinetic simulation has reported non-thermal tails at quasi-perpendicular shocks. Unlike 2D simulations, 3D runs show that protons develop a non-thermal tail spontaneously. They are rapidly accelerated via shock drift acceleration up to a maximum energy determined by their escape upstream. We discuss the implications of our results for the phenomenology of heliospheric shocks, supernova remnants, and radio supernovae.

Speaker: Luca Orusa

100 From Microphysical Theory to Multi-Messenger Observations: A Semi-Analytic Approach to Cosmic Ray Acceleration

Interpreting observations of extreme astrophysical phenomena requires a detailed understanding of the microphysical processes responsible for cosmic ray acceleration. In the standard picture, supernova remnants and other astrophysical shocks accelerate these particles via diffusive shock acceleration (DSA), an efficient mechanism that produces power-law distributions in momentum. However, both the multi-wavelength emission from astrophysical shocks—in particular, supernova remnants—and the populations of CRs detected at Earth reveal discrepancies between this standard theory and observations. To address these discrepancies, I will present fast, semi-analytic modeling framework that self-consistently incorporates findings from state-of-the-art kinetic simulations. I will show how this model can address key tensions between theory and observations and make predictions for multi-messenger observations. In particular, I will apply this model to a variety of astrophysical objects, including supernova remnants, novae, and winds launched by active galactic nuclei.

Speaker: Rebecca Diesing (Institute for Advanced Study and Columbia University)

TeVPA2024_Diesing.pdf

TeVPA2024_Diesing.pptx

101 Acceleration of particles at the border of binary systems

Sources of ultra-high energy cosmic rays (UHECRs) are still not clear. UHECRs encompass the most energetic particles detected by ground experiments. Their sources could be neutron stars ($l \sim 10$ km), AGNs ($l \sim 10$ kpc) and even Galaxy clusters ($l \sim 1$ Mpc). It is well accepted that the production mechanisms for cosmic rays from many sources, bellow the Greisen-Zatsepin-Kuzmin (GZK) cuttoff, are the Fermi mechanism, diffuse shock acceleration, magnetic reconnection, among others. In particular, UHECRs propagate with energies beyond GZK ($> 10^{19}$ eV). Ultra high center-of-mass energies for particle collisions near coalescent binary systems of neutron stars (NSs) and black holes (BHs) could explain part of the UHECR source conumdrum. Therefore, it is natural to look at UHECRs and their byproducts from binary systems. Here we use perspectives of the so called Penrose Process to calculate the possible particle energy upper limit at the border of binary systems. In the present approach, the maximum energy comes from a combination of the Wald mechanism and the Bañados-Silk-West (BSW) effect. Here, details on the BSW effect are plentifully discussed as a collisional phenomenon from where the form factor of the center-of-mass energy of particles comes.

Speaker: Carlos Coimbra-Araújo

Parallel Session: Direct Detection

Convener: Leah Jenks (The University of Chicago)

102 Basic Energy-Threshold Modeling for Snowball Chambers

Cloud and bubble chambers have historically been used for particle detection, capitalizing on supersaturation and superheating, respectively. Now we will present new results from a prototype snowball chamber, in which an incoming particle triggers crystallization of a purified, supercooled liquid. We demonstrate, for the first time, simulation agreement with our first results from 5 years ago: the higher temperature of the freezing of water and significantly shorter time spent supercooled with respect to control in the presence of a Cf-252 fission neutron source. This is accomplished by combining Geant4 modeling of neutron interactions with the Seitz nucleation model used in superheated bubble chambers, including those seeking dark matter. We explore the possible implications of using this new technology for GeV-TeV scale WIMP searches, especially in terms of spin-dependent proton coupling, and report the first supercooling of WbLS (water-based liquid scintillator).

Speaker: Matthew Szydagis (UAlbany SUNY)

Evt14BNL.mp4

FLIR.mov

SnowTeVPA.pdf

SnowTeVPA.pptx

103 PICO bubble chambers for the direct detection of dark matter

The PICO collaboration uses bubble chambers to search for dark matter. The degree of superheat is chosen so that the detectors are insensitive to electron recoils; only nuclear recoils above several keV produce bubbles. C3F8 is used as the target fluid; the fluorination is ideally suited for investigating spin-dependent WIMP-proton interactions. The PICO-40L detector, currently being commissioned at the SNOLAB underground research facility, employs a "Right Side Up" geometry, putting the detector compression and expansion system below the target fluid in order to suppress backgrounds seen in previous PICO detectors. PICO-500, the next-generation detector with a projected exposure on the scale of a ton-year, is nearing the installation phase at SNOLAB. This talk will give an overview of the PICO detectors, including improvements in design and background mitigation techniques, as well as results from early commissioning of PICO-40L.

Speaker: Orin Harris (Northeastern Illinois University)

Orin_TeVPa_2024.pdf

104 Status of the COSINE-100 dark matter search experiment

The COSINE-100 experiment aims to investigate the dark matter-induced annual modulation signal previously observed by the DAMA/LIBRA experiment. Commencing its physics operations in September 2016, the experiment concluded its initial phase in March 2023 at the Yangyang underground laboratory in Korea, employing 106 kg of low-background NaI(Tl) detectors. To further enhance light collection capabilities, the detector has been upgraded for continued research at the Yemilab, a new underground laboratory in Korea. In this presentation, we provide an overview of the experiment's current status, along with recent physics results, including a comprehensive analysis of the annual modulation search utilizing the complete COSINE-100 dataset.

Speaker: Hyunsu Lee (Institute for Basic Science)

COSINE_TEVPA2024_HSLee.pdf

105 Scintillating Bubble Chambers for Direct Dark Matter Detection, and an Update on SBC-LAr10

The Scintillating Bubble Chamber (SBC) Collaboration aims to use the liquid-noble bubble chamber technology as a low-threshold detector for dark matter particles of 1-10 GeV/c². The detector combines the remarkable electron recoil (ER) discrimination of the bubble chamber with the event-by-event energy resolution provided by liquid argon (LAr) scintillation, with the crucial added benefit that ER discrimination in liquid-noble bubble chambers extends to much lower thresholds than in past freon-filled bubble chambers, with the potential for quasi-background-free operation at thresholds of 100 eV in nuclear recoil (NR) energy. SBC has developed two functionally identical 10 kg detectors: SBC-LAr10 at Fermilab will calibrate low-threshold performance, while the radio-pure SBC-SNOLAB chamber will execute SBC’s first deep-underground dark matter search. SBC-LAr10 at Fermilab was recently installed in the MINOS tunnel 100 meters underground, and the first bubbles are expected this fall. I will present the current status of SBC-LAr10 and describe the suite of gamma and neutron calibrations we will execute. The calibrations will confirm the physics reach of this new technology, motivating not just the SBC-SNOLAB chamber now being assembled but also future searches into the solar neutrino fog at 1 GeV/c².

Speaker: Zhiheng Sheng (Northwestern University)

Zhiheng Sheng Scintillating Bubble Chamber.pdf

106 Possible Direction Sensitivity for Short Tracks in LAr

A powerful beacon for penetrating the Neutrino Fog obscuring direct detection of heavy dark matter would be direction-sensitive detection of the recoil atoms. Negative-ion drift is being pursued for this purpose by a number of collaborations, but it is hard to see how this could achieve sensitive mass competitive with noble liquid TPCs. Direction sensitivity based on columnar recombination differences with respect to the electric drift field is well established for higher energy tracks in LAr. However, attempts to observe it in the liquid have not yielded statistically significant positive results. However, a 1994 experiment drifting charged tracks in LAr in the presence of a magnetic field as well, revealed substantial electron (v×B) drift, abeit operating at elevated temperature and pressure (T ≥ 120 K, P ≥ 26 bar). This result would imply a sufficiently long mean free path for drifting charge to show a columnar recombination based directional effect. The physics background and prospects for seeking this effect will be discussed.

Speaker: Prof. Jeff Martoff (PNNL/Temple University)

Parallel Session: Gamma ray astronomy

Conveners: Anastasia Sokolenko, Manuel Meyer (University of Southern Denmark)

107 Commissioning and Preliminary Observation Results of SST-1M Cherenkov telescopes

Speaker: Thomas Tavernier (FZU - Institute of Physics of the Czech Academy of Sciences)

TEVPA_2024_tavernier_sst1m.pdf

108 Observations of the IC 443 region with HAWC

Speaker: Hugo Ayala (Pennsylvania State University)

ic443-hawc-ayala.pdf

109 Microquasars Detections with HAWC: Exploring the Intriguing V4641 Sgr

Speaker: Xiaojie Wang (Michigan Technological University)

XJWang_HAWC_Microquasars_TeVPA2024.pdf

110 Nonlinear feedback of the electrostatic instability on the blazar-induced pair beam and GeV cascade

Speaker: Mahmoud S A Alawashra (DESY)

MA_TeVPA24.pdf

111 Characterizing the Fermi-LAT high-latitude sky with simulation-based inference

Speaker: Christopher Eckner (Center for Astrophysics and Cosmology, University of Nova Gorica)

TeVPA2024_talk_ECKNER_v2.pdf

112 Status of the Schwarzschild-Couder Telescope project: Exploring an innovative technology for gamma-ray astrophysics

Speaker: Reshmi Mukherjee (Barnard College, Columbia University)

TeVPA2024 Mukherjee pSCT Overview.pdf

Parallel Session: Indirect Detection

Conveners: Elena Pinetti (Fermilab), Milena Crnogorcevic (Stockholm University/OKC)

113 Search for DM annihilation from extra-galactic point sources with IceCube

The various multi-messenger emission models for the Seyfert galaxy NGC 1068 suggest black hole vicinity as a probable region of neutrino production. Dark matter (DM) halos may have a spiked structure near the central supermassive blackhole (SMBH) where the rate of DM annihilation is boosted. Therefore, galaxies holding SMBHs could be the sources of neutrinos emission due to DM annihilation. This analysis selects in total 49 nearby AGNs from different catalogs with known SMBH masses. To estimate a reasonable J-factor of each source, a machine learning method is applied to estimate missing information. Using 11 years of IceCube “tracks” data, the sensitivity and discovery potential are calculated for both a stacking analysis with all sources, as well as for a catalog search using individual sources. Both analyses are performed with a power-law and a DM annihilation spectrum. In the case of non-detection, an upper limit on the thermally averaged dark matter self-annihilation cross-section will be set.

Speaker: Ruohan Li (TUM)

DMannihilationSMBH_RuohanLi_TeVPA2024.pdf

114 Cosmic Ray Boosted Dark Matter at IceCube

Cosmic ray (CR) upscattering of dark matter is one of the most straightforward mechanisms to accelerate ambient dark matter, making it detectable at high threshold, large volume experiments. In this work, we revisit CR upscattered dark matter signals at the IceCube detector, considering both proton and electron scattering, in the former case including both quasielastic and deep inelastic scattering. We consider both scalar and vector mediators over a wide range of mediator masses, and use lower energy IceCube data than has previously been used to constrain such models. We show that our analysis sets the strongest existing constraints on cosmic ray boosted dark matter over much of the eV - MeV mass range.

Speaker: Christopher Cappiello (Washington University in St. Louis)

TeVPA Cosmic Ray-Boosted Dark Matter at IceCube.pdf

115 Constraining BSM physics with galactic center gas clouds

Cold interstellar gas clouds are a powerful way of probing Beyond Standard Model (BSM) interactions, such as those of dark matter, through their calorimetric impact. The immense size and extremely long lifetime of these clouds makes them uniquely sensitive to a variety of BSM interactions, from those ultra-light dark matter acting like a classical background field to ultra-heavy composites objects. I will discuss the variety of BSM interactions that can be constrained using these gas clouds.

Speaker: Amit Bhoonah (University of Pittsburgh)

TeVPa.pdf

116 Heavy Dark Matter Annihilation Search Towards Dwarf Galaxies with the IceCube Neutrino Observatory.

Dwarf Spheroidal galaxies (dSphs) are suspected dark matter dense astrophysical objects within our galactic neighborhood. They are otherwise low of other high energy neutrino sources which makes them ideal dark matter targets. The previous IceCube dark matter search toward dSphs was performed with an incomplete detector with fewer strings and significantly less data. This iteration will include IceCube's 86 string with data from the Northern Hemisphere. This study is over a dark matter mass range not well explored ranging from hundreds of GeV to 100 PeV in dark matter mass. In the case of no signal, we will set limits on the velocity-weighted cross section.

Speaker: Daniel Salazar-Gallegos (Michigan State University)

TeVPA2024.pdf

117 The road to Higgsino dark matter

The nearly-pure thermal Higgsino remains one of our best-motivated and least-tested theories of dark matter. The shortest path to discovering such a candidate is likely via observations of TeV-scale gamma rays at the Galactic Center. In this talk I discuss the prospects of current and near future observatories for finding or ruling out Higgsino DM, and how underlying systematics and analysis strategies can affect these prospects. Among the consequences of our study is the finding that H.E.S.S., a leading atmospheric Cherenkov observatory, may have overstated some of their DM limits by close to an order of magnitude. In a future-facing direction, CTA represents substantial potential for a high-signifiance discovery in our future.

Speaker: Weishuang Linda Xu (UC Berkeley/LBNL)

TeVPA.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Ting Cheng

118 Next-Generation Diffuse Neutrino Combined Fit: Inclusion of Multi-Flavour Shower Events Partially Contained in IceCube

Recently, the IceCube Neutrino Observatory has reported a deviation from a single power law in the extragalactic diffuse neutrino flux. This deviation is primarily driven by the hardening of the low-energy flux below 30 TeV. However, the behavior of the spectrum at higher energies remains uncertain; it is unclear whether it continues, cuts off, or exhibits other features. Partially-contained cascades, which are all-flavour neutrinos with interaction vertices at the edge or outside of the detector instrumentation volume, could contribute to clarifying certainties of the spectrum at high energies. Utilizing a neural network-based event selection consisting of these all-flavour cascade events, and previously employed in the observation of Galactic neutrinos, we propose a combined event selection of neutrino cascades, both contained and partially contained, together with through-going and starting muon neutrino tracks. Incorporating the addition of this cascade event selection, recently improved understandings of the Antarctic ice, and updated modeling of the atmospheric neutrino background, sensitivities will be shown to probe features of the astrophysical spectrum.

Speaker: Zoe Rechav (University of Wisconsin Madison)

TevPA_Rechav_Zoe.pdf

119 TAMBO: Searching for Tau Neutrinos in the Peruvian Andes

The detection of high-energy astrophysical neutrinos by IceCube has opened a new window on our Universe. While IceCube has measured the flux of these neutrinos at energies up to several PeV, much remains to be discovered regarding their origin and nature. Currently, the discovery of point sources of neutrinos is hindered by atmospheric neutrino backgrounds; likewise, astrophysical neutrino flavor ratio measurements are limited by the difficulty of discriminating between electron and tau neutrinos.

TAMBO is a next-generation neutrino telescope specifically designed to detect tau neutrinos in the 1-100 PeV energy range. This tau neutrino specificity enables the low-background identification of astrophysical neutrino sources, as well as tests of the flavor ratio of astrophysical neutrinos. TAMBO will comprise an array of water Cherenkov and plastic scintillator detectors deployed on the face of the Colca Canyon in the Peruvian Andes, with its unique geometry facilitating the high-purity measurement of astrophysical tau neutrinos. In this talk, I will present the prospects of TAMBO in the context of next-generation neutrino observatories and provide an overview of its current status.

Speaker: Will Thompson (Harvard University)

TeVPA 2024.pdf

120 Measuring the Flavor of UHE Neutrinos with PUEO

The Payload for Ultrahigh Energy Observations (PUEO) experiment is an Antarctic balloon-borne detector targeting astrophysical neutrinos with energies exceeding 100 PeV. PUEO aims to observe neutrinos via the detection of coherent radio emission sourced from in-ice neutrino interactions. The dominant channel for these interactions is the charged current interaction, which produces both a recoiling nuclei and the corresponding charged lepton to the flavor of the parent neutrino. At high energies, both of these particles are capable of developing in-ice particle cascades, with the charged lepton capable of producing multiple secondary cascades through radiative losses in the ice. We model the radio emission from these multi-cascade events as it would be observed during PUEO’s flight and quantify the signal properties, providing an outlook on PUEO’s ability to make flavor measurements of neutrinos at the highest energies.

Speaker: Austin Cummings (Penn State)

121 Flavour Anisotropies in High-Evergy Astrophysical Neutrinos

The paradigm of the Standard Model of particle physics has only been extended, in the recent past, by the addition of neutrino masses and oscillations. Today, we can use neutrinos to verify our most fundamental theories, such as Lorentz invariance, which, if broken, introduces a preferred reference frame in the Universe. For neutrinos, the resulting phenomenology can predict flavour anisotropies dependent on the neutrino arrival directions, compounding over very large energies and propagation lengths. High-energy neutrinos from astrophysical sources are a unique probe into this parameter space at the highest energies available today and in the near-future. We use directional flavour compositions recovered from the IceCube High-Energy Starting Events (7.5 years of data) to place constraints on Lorentz invariance-violating parameters that generate flavour anisotropies.

Speaker: Bernanda Telalovic (Niels Bohr Institute, University of Copenhagen)

TeVPA_BernandaTelalovic.pdf

122 Physics results of KM3NeT and update on the construction phase

KM3NeT is a multi-site undersea neutrino telescope, designed to detect and study cosmic neutrinos and their sources in the Universe as well as to perform measurements of the neutrino oscillation parameters. In the Mediterranean Sea the ARCA (offshore Portopalo di Capo Passero, Italy) and ORCA (offshore Toulon, France) detectors are under construction, optimized for the detection of neutrinos with energies in the range of 1 TeV-100 PeV and 10 GeV-10 TeV, respectively. The construction of both detectors is well under way, with 28 and 23 detection units already installed in ARCA and ORCA respectively at the moment. In this talk we will report the main physics results obtained with ARCA and ORCA in their partial configurations, with an overview of the expected performance of the full detectors. The status and plans of construction of the detectors will be also illustrated. Finally, the KM3NeT alert system will be discussed in the context of a multi-messenger approach.

Speaker: Marco Cirella (INFN)

Talk_TeVPA2024_KM3NeT_MCircella.pdf

Parallel Session: Particle Physics/ Cosmology

Conveners: Huangyu Xiao (KICP and Fermilab), Jae Hyeok Chang (Fermilab and UIC)

123 Constraining the primordial black hole abundance via Big-Bang nucleosynthesis

We investigate the scenario in which primordial black holes (PBHs) with masses MPBH ≲ 109g undergo Hawking evaporation, around the Big-Bang nucleosynthesis (BBN) epoch. The evaporation process modifies the Universe’s expansion rate and the baryon-to-photon ratio, leading to an
alteration of the primordial abundance of light nuclei. We present upper bounds for the PBH relative abundance at formation in the range 108
g ≲ MPBH ≲ 109 g, providing the strongest constraints existing to-date
in this mass range.

Speaker: Fabio Iocco (Università di Napoli "Federico II")

124 Corrections to Hawking radiation from asteroid-mass primordial black holes: description of the stochastic charge effect in quantum electrodynamics

Hawking radiation sets stringent constraints on Primordial Black Holes (PBHs) as a dark matter candidate in the $M \sim 10^{16} \ \mathrm{g}$ regime based on the evaporation products such as photons, electrons, and positrons. This motivates the need for rigorous modeling of the Hawking emission spectrum. Using semi-classical arguments, Page [Phys. Rev. D 16, 2402 (1977)] showed that the emission of electrons and positrons is altered due to the black hole acquiring an equal and opposite charge to the emitted particle. The Poisson fluctuations of emitted particles cause the charge $Z|e|$ to random walk, but since the acquisition of charge increases the probability of the black hole emitting another charged particle of the same sign, the walk is biased toward $Z=0$, and approaches an equilibrium probability distribution with finite variance $\langle Z^2\rangle$. In this talk, we explore how this ''stochastic charge'' phenomenon arises from quantum electrodynamics (QED) on a Schwarzchild spacetime. We prove that (except for a small Fermi blocking term) the semi-classical variance $\langle Z^2 \rangle$ agrees with the variance of a quantum operator $\langle \hat{\cal Z}^2 \rangle$, where $\hat{\cal Z}$ may be thought of as an ''atomic number'' that includes the black hole as well as charge near it (weighted by a factor of $2M/r$). In QED, the flucutations in $\hat{\cal Z}$ do not arise from the black hole itself (whose charge remains fixed), but rather as a collective effect in the Hawking-emitted particles mediated by the long-range electromagnetic interaction. We find the rms charge $\langle Z^2\rangle^{1/2}$ asymptotes to 3.44 at small PBH masses $M\lesssim 2\times 10^{16}\,$g, declining to 2.42 at $M=5.2\times 10^{17}\,$g.

Speaker: Gabriel Vasquez (The Ohio State University)

TeVPA_talk.pdf

125 Exploding Primordial Black Holes

Primordial Black Holes (PBHs) could play a relevant role in several physical phenomena. They are particularly attractive as a candidate for dark matter, seeds of supermassive black holes, sources of gravitational waves, etc. In addition, the observation of an evaporating black hole would pro- vide definitive information on the elementary particles present in nature, including new degrees of freedom beyond the Standard Model. VHE gamma-ray observatories such as HAWC and LHAASO, among others, provide the technology to potentially detect such an extraordinary and unprecedented event. Although the PBH abundance is tightly constrained in the mass range of interest, we critically revisit the assumptions underlying the bounds and study how they are modified in alternative scenarios where a large number of degrees of freedom are introduced and provide a realistic assessment of the capacity of current and future VHE gamma-ray telescopes to detect an exploding PBH in the coming years. We also explore a new scenario based on the introduction of a new heavy dark electron that may lead to a large population of exploding black holes consistent with indirect bounds via the formation of quasi-extremal primordial black holes.

Speaker: Quim Iguaz Juan (UMass Amherst)

TeVPA_2024_PDF.pdf

126 Warm Hawking Relics From Primordial Black Hole Domination

Various cosmological scenarios give rise to primordial black holes in the early universe. If these black holes were light enough ($\lesssim 10^8$ g), they would have disappeared before BBN due to Hawking evaporation. Thus, their abundance is only weakly constrained by observations. Even if the abundance was small, the universe could have gone through an era of black-hole domination before they evaporated, in which case the hot plasma that seeded nucleosynthesis was reheated entirely from their evaporation. I will introduce Hawking relics: stable, dark-sector particles produced alongside the Standard Model by Hawking evaporating primordial black holes. If massive, these relics would act as warm dark matter, suppressing the growth of structure. I will show that Hawking relics are produced with much larger momenta, but in smaller quantities than the familiar thermal relics considered in standard cosmology. Consequently, Hawking relics with keV–MeV masses affect cosmology in a similar way to eV-scale thermal relics like massive neutrinos. I will discuss how the detailed momentum distribution generated by Hawking evaporation gives these relics a distinctive signature in the matter power spectrum. Finally, I will introduce new constraints on the fraction of dark matter in Hawking relics from cosmological data.

Speaker: Christopher Shallue (Harvard)

127 Dark Matter Primordial Black Holes from Warm Natural Inflation

In previous work [1] we have shown that within the natural warm inflationary paradigm (WNI) observational constraints on the primordial power spectrum from the cosmic microwave background (CMB) can be satisfied without going beyond the Planck scale of the effective field theory. Moreover, WNI can inevitably provide perfect conditions for the production of primordial black holes (PBHs) in the allowed window of black-hole mass range ($10^{-16}- 10^{-11}$ M$_\odot$) where it can account for all of the the dark matter content of the universe while satisfying observational constraints. In this talk we review the contributions from this form of dark matter to the gravitational wave background [2], and the prospects for this PBH dark matter to merge into early seeds of galaxy formation and super-massive black holes at high redshift.

[1] M. Correa, M. R. Gangopadhyay, N. Jaman, G. J. Mathews, Phys. Lett. B835, 137510 (2022).
[2] M. Correa, M. R. Gangopadhyay, N. Jaman, G. J. Mathews, Phys. Rev. D109, 063539 (2024).

*Work at the University of Notre Dame supported by the U.S. DOE under nuclear theory grant DE-FG02-95-ER40934

Speaker: Grant Mathews (University of Notre Dame)

Wednesday, August 28

Registration: Breakfast

Plenary Session

128 Dark Matter Icebergs

In this talk, I’ll discuss the status and prospects of direct searches for >1 GeV dark matter, which includes TeV-scale astrophysical particles!

Speaker: Matthew Szydagis (UAlbany SUNY)

Lippincott_TeVPA2024.pdf

129 Low frequency dark matter waves: a forecast

Decades of astrophysical observations point to the existence of a feebly interacting particle comprising 85% of the matter content of the universe. A promising candidate is the QCD axion, a natural product of the Peccei-Quinn mechanism that solves the strong CP problem. This talk will focus on the use of resonant haloscopes to search for axion dark matter, notably, the Axion Dark Matter eXperiment (ADMX) and the DMRadio experiment. I will present the most recent results from ADMX and the plan for the forthcoming ADMX-EFR experiment, which uses a multi-cavity array to search for dark matter. I will also discuss progress in the design and commissioning of the DMRadio-50L experiment, which will serve as a quantum testbed, as well as the DMRadio-m3 experiment, which targets the DFSZ axion at sub-ueV masses

Speaker: Chelsea Bartram (University of Washington)

TeVPa_Chelsea.pdf

130 Dark Matter Ripples: High-Mass Axions and Low-Mass Fermions

I will discuss direct detection prospects for meV-GeV scale dark matter, including the SuperCDMS SNOLAB dark matter program, R&D towards meV-scale thresholds for scattering events, and new concepts in axion detection.

Speaker: Noah Kurinsky (Stanford)

TeVPa24.pdf

10:30 AM Coffee break

Plenary Session

131 Active Galactic Nuclei as Counterparts of IceCube Neutrinos

The detection of high-energy neutrinos by the IceCube Neutrino Observatory has opened a new window into the study of astrophysical sources, in particular Active Galactic Nuclei (AGN). Both jetted and non-jetted AGN are prime candidates for these neutrinos. This talk will review recent evidence linking specific AGN to IceCube neutrino events. I will show how multi-wavelength observations can be used to pinpoint the regions from which these neutrinos might originate, often tracing them back to regions close to supermassive black holes. The identification of these regions raises new questions about the acceleration processes and the origin of the IceCube neutrinos. Future neutrino telescopes will be essential to test and confirm these initial associations, and to explore environments and mechanisms in our Universe that are otherwise inaccessible to electromagnetic radiation

Speaker: Elisa Resconi (TUM)

TeVPa-Resconi-24.pdf

132 Experimental searches for ultra-high-energy neutrinos

Ultra-high energy neutrinos (>100 PeV) are expected to be unique messengers to the distant universe. This is because the other classic UHE messengers--photons and cosmic rays--are attenuated for sources further away than ~100 MPc. Additionally, as neutral and weakly interacting particles, neutrinos travel in straight lines, and so they point at their sources. However, the flux of UHE neutrinos is expected to be extremely low, requiring immense detectors approaching 100 km2 in size. In this talk, I will overview existing and future experimental efforts to find this UHE flux, most of which rely on the radio-Cherenkov (Askaryan) emission produced in neutrino nucleon interactions in dense media such as glacial ice.

Speaker: Brian Clark (University of Maryland)

tevpa_clark.pdf

133 Galactic and Extragalactic Neutrino Factories

Over a decade after the discovery of diffuse astrophysical neutrinos, the first evidence of individual neutrino sources has emerged. These sources exhibit several distinct characteristics: 1) they are powerful and abundant; 2) they are likely opaque to the gamma rays that accompany neutrino production; and 3) extragalactic neutrino emitters are significantly more powerful than Galactic ones. This presentation will explore the astrophysical environments that may produce the bulk of the diffuse neutrinos observed by IceCube, with a particular focus on active galactic nuclei. Additionally, we will discuss how recent observations of the neutrino emission from the Galactic Plane enhance our understanding of Galactic PeVatrons and their implications for future astroparticle studies at TeV-PeV energies.

Speaker: Ke Fang (University of Wisconsin-Madison)

TeVPA_Fang_Aug2024.pdf

12:30 PM Lunch

Parallel Session: Dark Matter

Conveners: David Cyncynates (University of Washington, Seattle), Gordan Krnjaic (The University of Chicago)

134 (Can you) Infer the dark matter profile of the Milky Way from its circular velocity curve

The circular velocity curve, one of the first pieces of evidence for dark matter (DM), is a direct probe of the Galaxy’s potential, which allows studies of the nature of DM. Recent large surveys have provided valuable information for determining the Milky Way circular velocity curve.

In this talk, I will describe our recently derived circular velocity curve of the Milky Way out to ~30 kpc, which shows a sharp decline at R greater than 20 kpc. We find that a cored Einasto profile with slope parameter 1.13 +/- 0.06 is a better fit to the data than a generalized or contracted Navarro-Frank-White (NFW), as was argued in previous studies. We also find the virial mass of the DM halo to be significantly lower than previous estimates, but the corresponding local DM density at the solar position is consistent with the literature.

To better understand potential systematics underlying the measurement, we conduct follow-up tests using the FIRE simulation and synthetic surveys. We specifically replicate the sample selection and Jeans’ equation calculation. We find that higher-order drift correction, non-axisymmetry, and dynamical disequilibrium induced by merger events can introduce biases in the measured curve. As a result, the circular velocity curve of the Milky Way should be interpreted with caution, and additional systematic uncertainties must be incorporated when inferring the dark matter profile.

Speaker: Xiaowei Ou (Massachusetts Institute of Technology)

20240827_TeVPA.pptx

20240827_TeVPA_XOu.pdf

135 Cosmological profile likelihood constraints on dark matter-baryon scattering

While direct and indirect detection experiments have yet to find dark matter interacting with standard model particles, cosmological probes provide a complementary approach for exploring the physics of dark matter. Phenomenological dark matter-baryon scattering models can probe several particle physics scenarios with cosmological data. These models have two parameters vulnerable to prior volume effects, namely the scattering cross section and the fraction of dark matter that interacts with standard model particles. As either parameter approaches its standard model value, the prior volume becomes unconstrained, resulting in a posterior distribution that is biased towards this region. I will present preliminary results of a frequentist approach using profile likelihoods to constrain dark matter-baryon scattering using observations of the cosmic microwave background.

Speaker: Maria Straight (The University of Texas at Austin)

136 Giant planet airglow induced by dark matter annihilation

We investigate dark matter capture and annihilation in the Solar System's giant planets, leading to ionization in their atmospheres. Using UV spectrum data from spaceprobe flybys observing the nightside of these planets, we avoid contamination coming from solar reflection. We find an enhanced sensitivity for dark matter masses below 1 GeV, particularly for spin-independent and proton spin-dependent scattering cross sections, surpassing current direct detection experiments, and reaching down to about $10^{-40}$ cm$^2$. Our results highlight planetary spectroscopy as a complementary approach to probing dark matter properties.

Speaker: Marianne Moore (MIT)

TeVPA_airglow.pdf

137 The timescales for dark matter heating of old neutron stars

Neutron stars (NSs) are promising cosmic laboratories to test the nature of dark matter (DM). DM captured by the strong gravitational field of these stellar remnants transfers its kinetic energy to the star through subsequent collisions with the star constituents. Further DM annihilation can add extra heating. This can produce anomalous heating of old neutron stars. While DM deposits its kinetic energy quite quickly, in order for appreciable annihilation heating to be achieved, capture and annihilation processes should reach a state of equilibrium. In light of this, we revisit the calculation of the DM capture rate, thermalization, and capture-annihilation equilibrium timescales in NSs, making little approximations about the physics of neutron stars. We show that capture-annihilation equilibrium, and hence maximal annihilation heating, can be achieved without complete thermalization of the captured dark matter for all types of dark matter - baryon interactions. This includes cases where the scattering or annihilation cross sections are momentum or velocity suppressed in the non-relativistic limit. For scattering cross sections that saturate the capture rate, we find that capture-annihilation equilibrium is typically reached on a timescale of less than a year for vector interactions and $10^4$ years for scalar interactions.

Speaker: Sandra Robles (Fermilab)

Timescales_DM_heating_NS_TeVPA.pdf

138 Searching for dark matter with molecular targets in astrophysical objects

The age of WIMP-like dark matter direct detection is drawing to a close due to their non-detection at exquisitely sensitive liquid-noble detectors. However, models where the dark matter is lighter than the mass of a proton remain largely inaccessible to experimental probes. Recently, molecular targets have emerged as particularly well-suited detector materials to look for this sub-GeV dark matter. In this talk, I will review the latest development in molecule-based detection techniques. Then, I will show how the theoretical basis of these detection strategies can be applied to astrophysical objects in order to probe previously unexplored parameter space. In particular, I will present powerful new constraints on sub-GeV dark matter from molecular signatures in Jupiter and other solar system planets. Then, I will show how similar considerations applied to cold molecular clouds in the milky way are used to derive some of the strongest constraints on strongly-coupled subcomponent dark matter.

Speaker: Carlos Blanco (Princeton University)

Parallel Session: Gamma ray astronomy

Conveners: Anastasia Sokolenko, Christopher Eckner (Center for Astrophysics and Cosmology, University of Nova Gorica)

139 10 years of ultra-high-energy science with HAWC

Speaker: Kelly Malone (Los Alamos National Laboratory)

TeVPAPresentationMalone.pdf

140 VERITAS follow-up of newly identified LHAASO sources

Speaker: Samantha Wong (McGill University)

lhaaso_tevpa.pdf

141 Morphological and Spectral Studies on SS 433 Jet Lobes with HAWC

Speaker: Chang Dong Rho (Sungkyunkwan University)

tevpa2024.pdf

142 Do the LHAASO Galactic diffuse emission data require a contribution from unresolved sources?

Speaker: Vittoria Vecchiotti (NTNU)

TeVPa 2024 (LHAASO).pdf

143 Unraveling the Complex Gamma-Ray Emission from eHWC J1825-134 Region with HAWC: the Transition of TeV Halo

Speaker: Dezhi Huang (University of Maryland)

J1825-TeVPa-2024.pdf

144 Origin of Diffuse Gamma Rays Detected above 398 TeV by the Tibet ASγ Experiment

Speaker: Sei Kato (Institute for Cosmic Ray Research)

Parallel Session: HE Astro / Gravitational Waves

Conveners: Ariane Dekker (The University of Chicago), Garv Chauhan (Virginia Tech)

145 Variability of the Galactic CRs and Diffuse Gamma-Ray Emission Predicted with GALPROP

Using the 3D simulation option of the GALPROP framework we modelled Galactic cosmic-ray (CR) diffusion utilising a distribution of CR sources stochastically placed in position and time within the Galaxy. This source distribution more accurately represents the formation rates and finite lifetimes compared to the steady-state CR injection models that are typically assumed.
We investigate the time variability of the diffuse gamma-ray emission along the Galactic plane.

Our results show that the leptonic component of the gamma-ray emission is highly sensitive to the assumed electron injection and spectral characteristics. Furthermore, the leptonic component is heavily dependent on the positions of the sources due to the rapid synchrotron cooling of the very-high-energy electrons. As the gamma-ray energy increases so does the magnitude of the variations in the total diffuse flux. At 100 GeV the variations due only to the stochastic nature of the CR electron source placement can be as large as 30 percent in the outer Galaxy, increasing to an order of magnitude at 10 TeV.

Considering the placement of the CR sources is critical in connecting the Galactic diffuse emission across the GeV--PeV regimes. The variations induced by the stochastic CR electron source placement predict emissions consistent with those inferred from the H.E.S.S. Galactic plane survey. Additionally, these variations provide a natural explanation for the observed excess gamma-ray emission measured by LHAASO without ad-hoc tuning of the models.

Speaker: Dr Peter Marinos (Stanford University)

2024_08_TeVPA_Slides.pdf

146 Pulsar gamma ray halos and implications on cosmic rays propagation

add later

Speaker: Xiaojun Bi (IHEP, China)

TeVPA2024.pdf

147 Search for neutrino signals from the Galactic plane and Cygnus Bubble based on LHAASO γ-ray observations

High-energy neutrino and γ-ray emission are expected from the Galactic plane, generated by interactions between cosmic rays and the interstellar medium or radiation fields. Recent observations from LHAASO have detected diffuse γ-rays from the Galactic plane and an ultrahigh-energy γ-ray bubble (Cygnus Bubble) in the Cygnus region up to PeV energies, suggesting the possibility of neutrino emission. Using publicly available 7 years of IceCube track data with the full detector, we conducted searches for neutrino signals correlated with LHAASO diffuse Galactic γ-ray emission and Cygnus Bubble with a template method. A mild excess of neutrinos is observed in the Galactic plane. We will present results from these searches.

Speaker: Wenlian Li (Tsung-Dao Lee Institute, Shanghai Jiao Tong University)

TeVPA2024_Galactic_Plane_Neutrino_20240828_upload.pdf

148 TeV Halos: A New Class of Gamma-Ray Sources Provide Insight into Galactic Diffusion

Observations by the HAWC and HESS telescopes have found extended TeV emission consistent with a handful of young and middle-aged pulsars. In this talk, I will show that these detections have significant implications for our understanding of both pulsar emission and TeV astrophysics. Most importantly, the high-luminosity and spatial extension of TeV halos indicate that cosmic-ray diffusion on 20-50 pc scales surrounding energetic sources is atypical of the standard interstellar medium. Four models have been proposed, including those where locally anisotropic diffusion creates an appearance of a concentrated source from certain viewing angles, models which invoke rectilinear transport to produce a compact spatial profile in an otherwise standard diffusion environment, models where some pulsars fortuitously pockets of low-diffusion, and finally models where the pulsar (or associated supernova remnant) actively inhibit diffusion on moderate spatial scales. I will review each model, and argue that current observations prefer models where energetic sources actively inhibit diffusion in their surrounding environment.

Speaker: Tim Linden (Stockholm University)

tevpa2024_linden.pdf

149 Multi-wavelength Emission from Relativistic Jets and A Magnetically Arrested Disk of Cygnus X-1

Black hole binaries are observed from radio to gamma rays. While it is believed that the radio and X-ray emission comes from relativistic jets and accretion flows, respectively, the origin of the gamma-ray emission is still under debate. When a black hole binary is in the hard state, it likely has a magnetically arrested disk (MAD), where the magnetic flux threading the black hole is in a saturation level. We consider a scenario where the multi-wavelength emission of a binary comes from the jets and MAD. We apply such a two-zone model to the well measured Galactic binary Cygnus X-1. In our model, electrons and protons in the MAD are heated and accelerated by the turbulence, while electrons in the jet are accelerated by magnetic reconnection. Thermal electrons in the accretion flows produce X-ray emission by up-scattering photons from the standard disk. Nonthermal electrons in the jets produce radio and gamma-ray emission through synchrotron radiation and synchrotron self-Compton processes, respectively. Protons accelerated in the MAD emit very-high-energy gamma-rays and neutrinos through hadronuclear interaction and photomeson production. We demonstrate that the model may explain the multi-wavelength emission and predict that the TeV gamma-ray and neutrino emission of Cygnus X-1 may be observed by future experiments.

Speaker: Riku Kuze (Tohoku University)

TeVPA2024_RK_BHXB.pdf

Parallel Session: Indirect Detection

Conveners: Elena Pinetti (Fermilab), Lena Rathmann (RWTH Aachen University)

150 Search for heavy dark matter with Fermi LAT

The Fermi Large Area Telescope, with its exceptional sensitivity, has played a crucial role in the indirect search for Weakly Interacting Massive Particles (WIMPs) as dark matter (DM) candidates using gamma rays. However, the domain of dark matter with masses exceeding TeV energies remains less explored. In the case of such heavy dark matter, secondary gamma rays can be produced when high-energy electrons and positrons, resulting from the annihilation or decay of heavy dark matter, lose energy through inverse Compton and synchrotron emissions in the interstellar environment. By searching for these secondary emissions, we can extend the scope of LAT's dark matter search to include more massive dark matter candidates. In this talk, we present recent results on the search for heavy dark matter using 14 years of the Fermi Large Area Telescope (LAT) observations towards nearby dwarf spheroidal galaxies and galaxy clusters. We will show how our extended search strategy has led to stringent constraints on the annihilation and decay of heavy dark matter, which are competitive with those from other high-energy gamma-ray instruments. We also examine a variety of systematic uncertainties associated with the assumptions made in calculating these secondary emissions to demonstrate the robustness of our constraints.

Speaker: Dr Deheng Song (Kyoto University)

Fermi-HDM-Song-TeVPa.pdf

151 Testing Wino Dark Matter with VERITAS Dwarf Galaxy Observations

Adding an electroweak triplet fermion, or wino, to the Standard Model gives one of the simplest particle explanations of dark matter. In addition to this bottom-up, economical motivation, such a state automatically arises in supersymmetric extensions of particle physics. For masses near 2.8 TeV, its relic density from thermal freezeout would provide a complete resolution of the dark matter puzzle. Since the wino participates in Standard Model gauge interactions, its annihilation produces energetic, nearly monochromatic gamma-ray photons. It is thus a prime target for indirect detection. We report here limits on the wino annihilation rate for masses from 800 GeV to 200 TeV using 638 hours of observation time on 17 dwarf spheroidal galaxies (dSphs) by the VERITAS imaging atmospheric Cherenkov telescope array. We utilize state-of-the-art theoretical calculations for the annihilation rate to photons and a conservative set of J-factors. While the existence of wino dark matter remains consistent with observation throughout much of the range we tested, this work shows that further study of dSphs offer a means to rule on this compelling model independent of Galactic Center observations.

Speaker: Matthew Baumgart (Arizona State University)

winoVERTIAS2024TeVPA.pdf

152 Indirect Searches for Ultraheavy Dark Matter in the Time Domain

Dark matter may exist today in the form of ultraheavy composite bound states. Collisions between such dark matter bound states may release intense bursts of radiation that include gamma rays among the final products appearing as gamma ray transients. Given their $\textit{a priori}$ unknown durations and occurrence rates, such bursts may have been missed not necessarily because of their low arriving gamma-ray fluxes, but rather their briefness and rareness. In this talk, I will discuss the strategies and prospects for discovering those intense bursts whose non-detection thus far is due to the latter. In particular, if these bursts originate from collisions of dark matter bound states, imaging atmospheric Cherenkov telescopes (IACTs) and Pulsed All-Sky Near-infrared and Optical Search for Extra-Terrestrial Intelligence (PANOSETI) can probe a large dark matter parameter space beyond existing limits. I will also present a concrete dark matter model that produces bursts potentially detectable in these instruments.

Speaker: Xuheng Luo (Johns Hopkins University)

Xuheng_TeVPa2024.pptx

153 Particle dark matter searches through cross-correlations

The talk will provide an updated overview of the search for particle dark matter signals by means of cross-correlations between multiwavelength observations, with special focus on the gamma-ray band, and large scale structure tracers like galaxy and galaxy cluster distributions and cosmic voids.

Speaker: Nicolao Fornengo (University of Torino)

TeVPA2024.pdf

154 Dark Matter from Intermediate-Mass Black Holes with Fermi-LAT

The Fermi Large Area Telescope (LAT) has set stringent constraints on dark matter (DM) properties. We propose a comprehensive search for DM annihilation signals in highly concentrated DM regions, known as DM spikes, around intermediate-mass black holes (IMBHs). First, we investigate excess emission in dwarf active galactic nuclei (AGNs), likely hosting central IMBHs, due to classical astrophysical processes. Subsequently, we search for new physics and DM spikes within these systems. Here, we aim to enhance LAT's capabilities in indirect DM detection and advance our understanding of DM distributions around IMBHs. The results lay the groundwork for future research with next-generation observatories, including Rubin, COSI, Euclid, Roman, and LISA.

Speaker: Milena Crnogorcevic (Stockholm University/OKC)

tevpa2024_MC.pdf

155 Evidence of gamma-rays from intermediate-mass black holes in dwarf galaxies

Understanding intermediate-mass black holes (IMBHs) can provide crucial insights into active galactic nuclei (AGN) feedback, black hole-galaxy co-evolution, and the origins of supermassive black holes. One promising method to study IMBHs is by searching for their high-energy emission in nearby dwarf galaxies. Using 13 years of Fermi LAT observations, we conducted a stacking analysis to detect potential gamma-ray emissions from 135 dwarf galaxies with AGN activity signatures across different electromagnetic bands. We find slight evidence of gamma-ray emission from dwarf AGNs with a 2σ significance. Further examination of subsamples, categorized by their AGN signatures, yields up to 3σ significance. These findings hint at a potential gamma-ray signal from dwarf galaxies with active IMBHs.

Speaker: Rodrigo Nemmen (Universidade de Sao Paulo)

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Will Thompson (Harvard University)

156 Direct hits of atmospheric muons on neutrino detectors

Cosmic rays interact in the Earth's atmosphere to produce extensive air-showers (EASs). The EASs have Cherenkov and fluorescence emission associated to them that can be detected by ground-based, sub-orbital and satellite-based neutrino telescopes.
Ground-based and sub-orbital telescopes are also subject to the atmospheric flux of muons which arrive at the detectors as a potential background. Using a semi-analytic technique with cascade equations for atmospheric particle fluxes, we quantify the atmospheric muon flux that reaches ground-based and sub-orbital telescopes like Trinity and the Extreme Universe Space Observatory Super Pressure Balloon 2 (EUSO-SPB2), respectively. We evaluate the conventional muon flux produced from pion and kaon decays for muon energies higher than a few GeV for which the effects of Earth's magnetic field can be ignored.

Speaker: DIKSHA GARG (The University of Iowa)

atm_muons_tevpa.pdf

157 Design and Hardware Overview of PUEO

Planned to fly the Austral summer of 2025, the Payload for Ultrahigh Energy Observations (PUEO) is a balloon experiment built to search for Askaryan emission from showers from > EeV neutrinos and air showers from ultra-high energy cosmic rays (UHECRs). The instrument is designed to maximize sensitivity to these signals while rejecting backgrounds. The payload includes two instruments: the Main Instrument, boasting 96 quad-ridge horn antennas, and the Low-Frequency Instrument, comprising 8 sinuous antennas. Radio signals are measured in both polarizations per antenna, conditioned, and then sent to the DAQ system for triggering and readout before being saved to disk. PUEO’s design must also be within the power, weight, and telemetry constraints for long duration ballooning. This talk will present the design of PUEO in the context of measuring the science signals of interest and the current hardware being built for its 2025 launch.

Speaker: Rachel Scrandis (The University of Chicago)

Scrandis_TeVPAPresentation FINAL.pdf

158 The Radio-Neutrino Observatory in Greenland: Instrumentation Overview

The Radio Neutrino Observatory in Greenland (RNO-G) is situated at Summit Station and is intended to detect Askaryan emission from ultra-high energy neutrinos above 10 PeV. The detector is proposed to have 35 stations of which 7 have been installed so far. Each station consists of 3 strings carrying dipole antennas embedded down to 100 meters in ice. These antennas capture the horizontal and vertical polarization of the Askaryan signal and work in conjunction with shallow antennas. The detector is designed to trigger on impulsive radio signals from neutrino-nucleon interactions in the ice. This talk will overview the RNO-G instrument, including the overall station architecture, the antenna designs and performance, and the triggering and readout systems, which are all designed to lower thresholds and enhance sensitivity to neutrinos.

Speaker: Aishwarya Vijai (University of Maryland, College Park)

TeVPA Final.pdf

159 Particle Shower Simulation Studies for IceCube

The events detected by the IceCube Neutrino Observatory have two main topologies: cascades and tracks. Cascades are particle showers, and historically, due to their short extension (on the order of meters) relative to the spacing between optical modules, the main focus for cascade events has been on measuring the total light yield as a proxy for energy, rather than their spatial features. However, as our understanding of the medium improves and we broaden our spectrum of event selection techniques, IceCube becomes more sensitive to various subtle features of cascades. These features include the electromagnetic or hadronic origin of the shower, its charm content, longitudinal and transverse profiles, and the muonic component. We present detailed shower simulations generated by tailored software using an up-to-date hadronic interaction model and discuss the results and potential applications.

Speaker: Emre Yildizci (University of Wisconsin-Madison)

TeVPA Particle Shower Presentation.pdf

160 nuSpaceSim: A Comprehensive Simulation Package for Modeling the Response of Space-based Experiments to Upward-moving Extensive Air Showers sources by Cosmic Neutrinos in the Earth

Cosmic neutrinos are hadronic processes messengers and at high energies provide a clear window into their astrophysical sources. Starting around a PeV, Tau neutrino interactions within the Earth can provide a substantial flux of Earth-emergent tau-leptons which then decay to form upward-moving extensive air showers (EAS). This effectively uses the Earth as a neutrino target and the atmosphere as an optical and radio signal generator to form a detector with >> gigaton mass. nuSpaceSim is an end-to-end simulation that is has been developed to model this neutrino-induced Earth-emergent lepton all the relevant physical processes that describe the neutrino-induced Earth-emergent lepton chain to both design the next generation of balloon- and space-based experiments as well as understand the data from recent experiments such as EUSO-SPB2 and ANITA. The simulation chain includes the modeling of neutrino interactions inside the Earth that generate leptons, propagating the leptons through the Earth into the atmosphere, modeling the tau-lepton decays, forming composite EAS, generating the air optical Cherenkov and radio signals, modeling their propagation and attenuation through the atmosphere (including the effects of clouds and ionosphere), and modeling the response of detectors at an altitude defined by the user. In this talk, the nuSpaceSim software, physics modeling, and the cosmic neutrino measurement capabilities of example sub-orbital and space-based experimental configurations will be presented.

Speaker: John Krizmanic (NASA/GSFC)

nuSpaceSIm-Krizmanic-TevPA2024.pdf

161 Modeling the refractive index profile of polar ice with the Askaryan Radio Array

The Askaryan Radio Array (ARA) is an ultrahigh energy (UHE) neutrino experiment at the South Pole that aims to detect radio emissions from neutrino-induced particle showers using in-ice antennas buried up to 200m in depth. The depth-dependent refractive index profile in ice affects calibration efforts and neutrino sensitivity predictions of ARA as well as other UHE neutrino experiments at both South Pole and Summit Station, Greenland. We present an in-ice refractive index profile based on previous ice density data and constrained by radio signals received by ARA antennas. A pulser lowered into a borehole near ARA in the 2018-2019 summer season provides useful data in determining the refractive index profile of polar ice by comparing direct and refracted travel times at various pulser depths. Data from the 2018-2019 campaign strongly favors a glaciology motivated three-phase refractive index model over the single exponential scale height model which has been traditionally used.

Speaker: Kenny Couberly (University of Kansas)

Tevpa_slides.pdf

Parallel Session: Particle Physics/Cosmology

Conveners: Huangyu Xiao (KICP and Fermilab), Melissa Diamond (Queen's University)

162 Axion Production in Highly Magnetized Astrophysical Plasmas

Compact objects such as neutron stars possess some of the strongest electric and magnetic fields in the observed universe. Non-thermal electromagnetic emission from neutron stars is sourced in regions with accelerating electric fields, $\vec{E} \cdot {\vec{B}} \ne 0$. These regions are also very efficient axion factories. Once produced, axions may (1) convert to photons, giving rise to anomalous electromagnetic signatures, (2) remain gravitationally bound to the neutron star and form dense clouds that can grow over astrophysical timescales, or (3) propagate to Earth and imprint detectable signals in laboratory experiments. In this talk, I will provide an overview of recent work on probing axions with neutron stars, and discuss important next steps in this program.

Speaker: Anirudh Prabhu (Princeton University)

163 Axion-Photon Sensitivity with NuSTAR Observations of M82 and M87

Ultra-light axions with weak couplings to photons are motivated extensions of the Standard Model. We perform one of the most sensitive searches to-date for the existence of these particles with the NuSTAR telescope by searching for axion production in stars in the M82 starburst galaxy and the M87 central galaxy of the Virgo cluster. This involves a sum over the full stellar populations in these galaxies when computing the axion luminosity, as well as accounting for the conversion of axions to hard X-rays via magnetic field profiles from simulated IllustrisTNG analogue galaxies. We find no evidence for axions, and instead set robust constraints on the axion-photon coupling at the level of $|g_{a\gamma\gamma}| \lesssim 6.4 \times 10^{-13}$ GeV$^{-1}$ for $m_a \lesssim 10^{-10}$ eV at 95% confidence.

Speaker: Orion Ning (University of California, Berkeley)

OrionNing_TeVPA2024.pdf

164 ALP-Photon conversion in Neutron Stars

We study multiple corrections to the ALP-photon conversion process in neutron stars, especially the isolated ones. The result may inspire further studies.

Speaker: Lingfeng Li (Brown University)

NS_ALP_Conversion_TeVPA.pdf

165 What AGNs and GRBs tell us about axion-like particles

Active Galactic Nuclei (AGNs) and Gamma-ray Bursts (GRBs) are characterised by highly relativistic outflows. In the first part of the talk, I will discuss how the production of axion-like particles (ALPs) close to the central engine can, on the one hand, either power or disrupt the outflow, and on the other hand, can lead to various observational signatures involving either changes in the prompt photon flux from the source or time delay in the arrival of secondary photons, depending on the coupling of the ALP with Standard Model particles. The non-observation of reprocessed cascade emissions from AGNs and GRBs is usually translated to a limit on the intergalactic magnetic field (IGMF) if plasma instabilities do not play a significant role. In the second part of the talk, I will show how, in addition, ALP processes occurring in AGNs and GRBs can thus be used to modify and refine the IGMF limits.

Speaker: Dr Oindrila Ghosh (The Oskar Klein Centre, Stockholm University)

Oindrila_Ghosh_TeVPA_2024.pdf

166 Effects of Superradiance in Active Galactic Nuclei

A supermassive black hole (SMBH) at the core of an active galactic nucleus (AGN) provides room for the elusive ultra-light scalar particles (ULSP) to be produced through a phenomenon called $\textit{superradiance}$. This phenomenon produces a cloud of scalar particles around the black hole by draining its spin angular momentum. In this work, we present a study of the superradiant instability due to a scalar field in the vicinity of the central SMBH in an AGN. We begin by showing that the time-evolution of the gravitational coupling $\alpha$ in a realistic ambiance created by the accretion disk around the SMBH in AGN leads to interesting consequences such as the amplified growth of the scalar cloud, enhancement of the gravitational wave emission rate, and appearance of higher modes of superradiance within the age of the Universe. We then explore the consequence of superradiance on the characteristics of the AGN. Using the Novikov-Thorne model for an accretion disk, we divide the full spectrum into three wavelength bands- X-ray ($10^{-4}-10^{-2}~\mu$m), UV ($0.010-0.4~\mu$m), and Vis-IR ($0.4-100~\mu$m) and observe sudden drops in the time-variations of the luminosities across these bands and Eddington ratio ($f_{\textrm{Edd}}$) with a characteristic timescale of superradiance. Using a uniform distribution of spin and mass of the SMBHs in AGNs, we demonstrate the appearance of depleted regions and accumulations along the boundaries of these regions in the planes of different band-luminosities and $f_{\textrm{Edd}}$. Finally, we discuss some possible signatures of superradiance that can be drawn from the observed time-variation of the AGN luminosities.

Speaker: Priyanka Sarmah (Natinal Tsing Hua University, taiwan)

TeVPA_2024_Priyanka.pdf

167 Implications of ALP-photon conversion for the diffuse gamma-ray background associated with high-energy neutrinos

Some fraction of the diffuse photon background is supposed to be linked to high-energy neutrinos by astrophysical mechanisms of production and electromagnetic cascades. This article presents a simulation study of axion-like particles (ALPs) implications for that component, exploiting transport equations. Alternations of that spectrum due to ALP-photon conversion in the intergalactic magnetic field (IGMF) in the cases of various ALP parameters and mixing regimes at sources are studied. The results indicate considerable influence of IGMF-conversion on the ALP-photon flux even in the case of inverse ALP-photon coupling constant M equal to 10^11.5 GeV and some residual effects in the case of M=10^12 GeV. Furthermore, the scenario shows another aspect of a complex multimessenger interplay between IceCube and Fermi data, to a certain extent relieving the tension between them.

Speaker: Mr Kirill Riabtsev (University of Cambridge (2023-2024), Lomonosov MSU (2019-2023))

3:45 PM Coffee break

Parallel Session: Dark Matter

Conveners: Gordan Krnjaic, Saniya Heeba (McGill University)

168 Vectorlike Dark Confinement at Direct Detection Experiments

We highlight the existence of a residual symmetry in the IR phase of a broad class of confining dark sectors that suppresses their signals at direct detection experiments. Our conclusions apply to all vectorlike confining dark sectors, regardless of the number of flavors and color, confinement scale, and dark matter mass. Our results highlights the irreplaceable role of a continuing collider program for searching for vectorlike dark confinement.

Speaker: Pouya Asadi (University of Oregon)

TeVPA_2024_169.pdf

169 Dark matter direct detection in the presence of the Large Magellanic Cloud

The Large Magellanic Cloud (LMC) can significantly impact the dark matter halo of the Milky Way, and boost the dark matter velocity distribution in the Solar neighborhood. Cosmological simulations that sample potential Milky Way formation histories are powerful tools, which can be used to characterize the signatures of the LMC’s interaction with the Milky Way, and can provide crucial insight on the LMC’s effect on the local dark matter distribution. I will discuss the impact of the LMC on the local dark matter distribution in state-of-the-art cosmological simulations, and its implications for dark matter direct detection.

Speaker: Nassim Bozorgnia

Bozorgnia-TeVPA.pdf

170 The effect of the LMC on non standard interactions for future dark matter direct detection experiments

Previous studies have shown the effect of the Large Magellanic Cloud (LMC) on the local speed distribution of the dark matter particles. Since it dominates the high speed tail of the distribution and the gravitational interaction also boosts the solar neighbourhood dark matter particles to higher velocities, such an effect has an impact on direct detection searches. In this talk, I will discuss the impact of the LMC on the expected signals in different future direct detection experiments taking into account not only the standard spin-independent (dependent) signal but different dark matter - nucleon interaction types following the Non-Relativistic Effective Field Theory approach. Furthermore, I will discuss how the LMC affects the results in the case of inelastic dark matter.

Speaker: Javier Reynoso Cordova (University of Alberta)

TeVPa.pdf

171 Dark Matter Subhalo Abundance in the Solar Neighborhood and Its Effect on Direct Detections

Lambda cold dark matter (\Lambda CDM) is widely considered as the standard model of the Big Bang cosmology that contains a postulated new particle called dark matter (DM), which makes up for 85% of the matter of the universe. However, DM has yet to be detected non gravitationally. One of the major ways of probing it is through direct detection experiments measuring the cross section of dark matter particles scattering off nuclei. Additionally, under \Lambda CDM, DM clumps up into halos and subhalos, potentially affecting our direct detection measurements if they happen to fly past the solar system and temporarily boost the local dark matter density. In this talk, I will give an estimation of the local abundance of low mass subhalos in the solar neighborhood and discuss the effect of their existence on direct detection. I will first introduce the local differential number density of subhalos, focusing on the dark low mass subhalos.I will then define the encounter cross section and further introduce the differential encounter rate for a subhalo to scatter off the Earth gravitationally that allows us to give an expected total number of yearly encounter events. Finally, I will discuss how such events are expected to affect the direct detection experiments. Although the rate is found to be quite small for the lifetime of direct detection experiments, this study inspires us to look for new ways to study the low mass subhalos, potentially through effects that can accumulate through years such as paleo detectors, and thus enable us to explore the lower end of the mass spectrum where the particle nature of DM plays a more important role.

Speaker: Xiuyuan Zhang

TeVPa-slides.pdf

172 Broadening direct searches for light dark matter

Direct searches for low-mass DM were originally designed using the same conceptual picture as WIMP searches. However, over the last five years, the crucial role of in-medium effects has come into sharp focus. A new theoretical framework in the language of condensed matter physics has emerged for understanding the relationship between the properties of detector systems and their sensitivity to DM interactions. I will report on three recent advances that leverage this formalism to substantially broaden the design considerations for the next generation of experiments, and even extract new constraints from existing data. First, for DM–electron interactions, large new datasets generated by the materials science community have enabled the first data-driven search for optimal detector materials, which promises to significantly enhance the sensitivity of near-future experiments. Second, just as detectors designed to detect nuclear scattering have been used to study electronic scattering, I will explain how in-medium effects make the reverse possible as well, allowing us to set new limits on DM–nucleon scattering using the low-threshold detectors designed to detect electronic scattering. Third, with the advent of low-threshold detectors sensitive to energy deposits as low as 50 meV, we have finally entered the regime where the interaction rate can be significantly enhanced due to the geometry of the detector system. These three considerations promise to substantially accelerate the search for light DM in both mass and cross section over the coming years.

Speaker: Benjamin Lehmann (MIT)

lehmann_slides.pdf

173 The SABRE South Experiment at the Stawell Underground Physics Laboratory

The SABRE experiment aims to detect an annual rate modulation from dark matter interactions in ultra-high purity NaI(Tl) crystals in order to provide a model independent test of the signal observed by DAMA/LIBRA. It is made up of two separate detectors that rely on joint crystal R&D activity; SABRE South located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia, and SABRE North at the Laboratori Nazionali del Gran Sasso (LNGS).

SABRE South is designed to disentangle seasonal or site-related effects from the dark matter-like modulated signal by using an active veto and muon detection system. Ultra-high purity NaI(Tl) crystals are immersed in a Linear Alkyl Benzene (LAB) based liquid scintillator veto, further surrounded by passive steel and polyethylene shielding and a plastic scintillator muon veto. Significant work has been undertaken to understand and mitigate the background processes, taking into account radiation from the detector materials, from both intrinsic and cosmogenic activated processes, and to understand the performance of both the crystal and veto systems.

SUPL is a newly built facility located 1024 m underground (~2900 m water equivalent) within the Stawell Gold Mine and its construction has been completed in 2023.
The commissioning of SABRE South started in early 2024 and the first equipment including the muon detectors have been already installed in SUPL.

This talk will report on the general status of the SABRE South assembly, its expected performance, and the design of SUPL.

Speaker: Dr Irene Bolognino (The University of Adelaide, Adelaide, SA 5005, Australia. ARC Centre of Excellence for Dark Matter Particle Physics, Australia.)

Parallel Session: Gamma ray astronomy

Conveners: Anastasia Sokolenko, Vikram Dwarkadas (The University of Chicago)

174 Multiwave+B63length study of Galactic PeVatrons LHAASO J2108+5157 and LHAASO J0341+5258

Speaker: Priyadarshini Bangale (University of Delaware)

PBangale_LHAASO_sources_TeVPa2024.pdf

175 Stacking searches for TeV halos with HAWC

Speaker: Hongyi Wu (University of Wisconsin-Madison)

TeVPA TeV Halo v0.4.pdf

TeVPA TeV Halo v0.4.pptx

176 Analysis Results of HAWC Data Corresponding to 1LHAASO Sources Exclusively Linked to Fermi-LAT detected GeV Gamma Rays

Speaker: Tulun Ergin (Michigan State University, Physics and Astronomy Department)

TE_TeVPa2024_presented.pdf

177 Fermi-LAT analysis of the CSO NGC4278 detected by LHAASO

Speaker: Ettore Bronzini (University od Bologna & INAF-OAS)

Bronzini_TeVPA2024_v4.pdf

178 M87's Multi-Wavelength Behavior During the 2018 EHT Campaign including a very high energy gamma-ray flaring episode

Speaker: Alexander Hahn (Max Planck Institute for Physics)

M87_ahahn_TeVPA2024.pdf

179 Searching for the next GRB170817A with Swift BAT GUANO

Speaker: Jimmy DeLaunay (Penn State)

TeVPA2024JD.pdf

Parallel Session: HE Astro / Gravitational Waves

Conveners: Ariane Dekker (The University of Chicago), Mainak Mukhopadhyay (The Pennsylvania State University)

180 Crescendo Beyond the Horizon: More Gravitational Waves from Domain Walls Bounded by Inflated Cosmic Strings

Gravitational-wave (GW) signals offer unique probes into the early universe dynamics, particularly those from topological defects. We investigate a scenario involving a two-step phase transition resulting in a network of domain walls bound by cosmic strings. By introducing a period of inflation between the two phase transitions, we show that the stochastic GW signal can be greatly enhanced. The generality of the mechanism also allows the resulting signal to appear in a broad range of frequencies and can be discovered by a multitude of future probes, such as Pulsar Timing Arrays, and space- and ground-based observatories. We also offer a concrete model realization that relates the second phase transition to the epoch of inflation. In this model, the successful detection of the GW spectrum peak pinpoints the soft supersymmetry breaking scale and the domain wall tension.

Speaker: Yunjia Bao (University of Chicago)

Bao_TeVPA2024.pdf

181 Imprints of Early Universe Cosmology on Gravitational waves

We consider pre BBN energy injection via PBH evaporation or Moduli decay into universe and it's possible detection via Gravitational waves via phase transitions in hidden sectors. The energy injection leads to three correlated peaks gravitational wave signatures instead of the usual one peak. The resultant GW amplitude is also stronger than the usual scenario, and hence can be probed via upcoming GW observatories as well, leading to constraints on such early universe energy injections.

Speaker: Mudit Rai (TEXAS A&M UNIVERSITY)

GWkick.pdf

182 Supermassive binary black holes and EM counterparts

Supermassive binary black holes (SMBHBs) are by-products of our theories of galaxy formation, crucial gravitational wave (GW) sources that will be observed with future observatories such as LISA. In this talk, we will give an overview of the subject, focusing on the expected SMBHB electromagnetic counterparts. We will present new calculations of the EM emission that take into account the physics of accretion and jets and discuss the connection with GWs. SMBHBs should be accompanied by ultra-long multiwavelength bursts, strongly correlated with the GW signal.

Speaker: Prof. Rodrigo Nemmen (Universidade de Sao Paulo)

183 Wavefrontsensor for the Einstein Telescope

To enable the detection of gravitational waves, the state of the interferometer must be known as precisely as possible. We describe a wavefront sensor in form of a camera, measuring the phase and intensity of all facilitated sidebands simultaneous for the 1550 nm interferometer of the Einstein Telescope. As novel feature, a fiber array of 8 x 8 is used with each fiber read-out by an individual photodiode to prevent optical crosstalk. With no moving parts, dynamical back scattering of light is fully prevented at possible data rates of 1 MHz. The implementation, commissioning in the laboratory, performance and possible applications are presented in this work.

Speaker: Benjamin Schwab (ECAP, FAU Erlangen-Nürnberg)

2024_08_28_TevPa.pdf

184 Construction of the Very High Energy Gamma-Ray Spectrum in Centaurus A Based on Filamentary Jet Model

The nearest radio galaxy, Centaurus A, known for its large-scale jet, has been monitored by multiwavelength observations. Analysis of the Fermi-LAT and H.E.S.S. observation data in 2019 showed up an unnatural hardening in very high energy gamma-ray spectrum [1], and its origin is still a matter of controversy. Imaging analysis also reveals that gamma-rays are distributed over the entire jet, requiring ubiquitous particle acceleration source, such as stochastic or shear acceleration.

In this study, we attempt to explain the very high energy gamma-ray spectrum by our refined model of filamentary jet, coupled with diffusive shock acceleration scenario of electrons. Shock waves generated by intermittent mass ejection pass through the jet, to be observed as knot-like features. The shocks are expected to create numerous magnetized current filaments having various transverse sizes, as compatible with observed X-ray substructure of the knots. We construct the spectrum of synchrotron radiation from the accelerated electrons being trapped in the magnetized filaments of the knots, taking inverse cascade of the turbulent magnetic fields into consideration.

Here, we focus on the knots A and B, which are the brightest among the structures resolved by radio and X-rays. The gamma-ray spectrum is constructed by fitting the theoretical synchrotron spectrum to the observed radio and X-ray data and boosting the spectrum up to the higher energy via inverse Compton scattering process {\it in situ}. The point is that the knots A and B are overshadowed by dense dust lane, so that fluxes from infrared to ultraviolet have not been measured. Although this circumstance makes it difficult to fix physical parameters only by the synchrotron spectral fitting, the values of the key parameters could be identified within a narrow range with reference to the gamma-ray spectral analysis. We calculate the upscattered spectrum by taking into account the Klein-Nishina effect and enhanced radiative cooling effect by the filamentation instabilities, i.e., significant increase of emitting surface-to-volume ratio. Provided these effects, we are able to reproduce the unnatural hardening of very high energy gamma-rays by adding up the fluxes of the knots.

[1] Abdalla, H. et al., the H.E.S.S. Collaboration, Nature, vol. 582, 356. (2020)
Authors: Yasuko S. Honda, Mitsuru Honda

Speaker: Dr Yasuko Honda (Kindai University Technical College)

TeVPA.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Jose Carpio (University of Nevada Las Vegas)

185 Constraints on Heavy Asymmetric and Symmetric Dark Matter from the Glashow Resonance

The decay of asymmetric dark matter (ADM) can lead to distinct neutrino signatures characterized by an asymmetry between neutrinos and antineutrinos. In the high-energy regime, the Glashow resonant interaction $\bar{\nu}_{e} + e^{-} \rightarrow W^{-}$ yields an increase in sensitivity to the neutrino flux, and stands out as the only way of discerning the antineutrino component in the diffuse high-energy astrophysical neutrino flux. This offers a unique opportunity in the search for dark matter with masses above the PeV scale. In this talk, I will discuss the neutrino signal stemming from ADM decay, the constraints on ADM lifetime with the current IceCube observation of Glashow resonance, and the projected sensitivities with the next-generation neutrino telescopes. I will also show the improvement in the constraints on symmetric dark matter decay due to the Glashow Resonance.

Speaker: Qinrui Liu (Queen's University)

tevpa2024_qliu.pdf

186 Final state radiation from high and ultrahigh energy neutrino interactions

Charged leptons produced by high-energy and ultrahigh-energy neutrinos have a substantial probability of emitting prompt internal bremsstrahlung $\nu_\ell + N \rightarrow \ell + X + \gamma$. This can have important consequences for neutrino detection. We discuss observable consequences at high- and ultrahigh-energy neutrino telescopes and LHC's Forward Physics Facility. Logarithmic enhancements can be substantial (e.g.\ $\sim 20\%$) when either the charged lepton's energy, or the rest of the cascade, is measured. We comment on applications involving the inelasticity distribution including measurements of the $\nu/\bar{\nu}$ flux ratio, throughgoing muons, and double-bang signatures for high-energy neutrino observation. Furthermore, for ultrahigh-energy neutrino observation, we find that final state radiation affects flavor measurements and decreases the energy of both Earth-emergent tau leptons and regenerated tau neutrinos. Finally, for LHC's Forward Physics Facility, we find that final state radiation will impact future extractions of strange quark parton distribution functions. Final state radiation should be included in future analyses at neutrino telescopes and the Forward Physics Facility. (https://arxiv.org/abs/2403.07984)

Speaker: Bei Zhou (Fermilab & KICP)

20240828_TeVPA2024.pdf

187 Study of a Z’ model based on data from ANTARES and ICECUBE

Telescopes such as ANTARES and IceCube can detect ultra high-energy neutrinos from the atmosphere and outer space. The information carried by these neutrinos sheds light on new interactions of matter, not yet explained by the standard model of particle physics. Recently, strong constraints on these non-standard interactions were achieved by ANTARES and Icecube through events with energies up to the order of 10 TeV. We use these limits to study new physics in a framework of a simplified Z' model. The results obtained are compared with those from large hadron colliders, showing relevant and complementary information to conventional measurements. The details about that will be presented in this talk. ArXiv:2304.01388.

Speaker: Dr Alexander Parada Valencia (Escuela Superior de Administración Pública)

188 Imprints of High Energy Neutrino Magnetic Moment

The IceCube collaboration pioneered the detection of
order PeV neutrino events and the identification
of astrophysical sources of high-energy neutrinos. Furthermore,
astrophysical environment with large magnetic field is a
prerequisite for the acceleration of charged particles which source
high-energy neutrinos. While propagating through such magnetic field
environment, neutrinos experience spin precession induced by their
magnetic moments, which impacts their helicity and flavor
composition at Earth. In this talk, I will discuss the influence of
neutrino magnetic moment on both flavor composition of high-energy
neutrinos and Glashow resonance events at neutrino telescopes, such
as IceCube, by considering scenarios in which high-energy neutrinos
are produced in the vicinity of astrophysical objects with strong
magnetic field, such as magnetars.

Speaker: Ting Cheng

189 Effects of Biaxial Birefringence on Polarization Reconstruction for the Askaryan Radio Array

The Askaryan Radio Array (ARA) is an experiment with the goal of detecting ultra-high energy (>10 PeV) neutrinos at the South Pole for the first time. ARA uses arrays of antennas designed to detect radio-frequency radiation emitted from relativistic particle showers produced by neutrinos interacting within the ice. South Pole ice behaves as a biaxially birefringent medium at radio frequencies, causing the polarization of signals to rotate during propagation and to split into two rays propagating at different speeds. These effects depend on the signal’s direction and polarization. Modeling the effects of birefringence is necessary to ascertain the polarization where the radio signal was emitted. In addition, the time delay between the two rays is a signature of an in-ice interaction and provides information about the distance to the interaction, an ingredient in energy reconstruction that is the most difficult to measure. Quantifying effects from birefringence is also relevant for antenna design optimization. In this talk, I will discuss biaxial birefringence modeling for ARA, its impact on polarization reconstruction, and a comparison of polarization reconstruction on radio pulser measurements and simulations with biaxial birefringence.

Speaker: Alan Salcedo Gomez (The Ohio State University)

Birefringence_TeVPA.pdf

190 A high-efficiency UHE neutrino search combining the phased array and traditional antennas of the Askaryan Radio Array

The Askaryan Radio Array (ARA) is an in-ice ultra high energy (UHE, >10 PeV) neutrino experiment at the South Pole that aims to detect UHE-neutrino induced radio emission in ice. ARA consists of five independent stations each consisting of a cubical lattice of in-ice antenna clusters with side length ~10m buried ~200 m below the ice surface. The fifth station of ARA (A5) is special as this station has an additional central string, the phased array (PA), which provides an interferometric trigger that enables ARA to trigger on weak signals that are otherwise buried in noise. Leveraging the low threshold phased array trigger, ARA was the first radio neutrino experiment to demonstrate significant improvement in sensitivity to weak signals. In this talk, we will present initial results from a neutrino search on A5 combining information from both the traditional ARA antennas and the phased array antennas. We will show the improved vertex reconstruction achieved with this approach, and leveraging this improvement, we expect to enhance the analysis efficiency beyond what has been achieved previously by ARA. This analysis is the paradigmatic representation of future neutrino searches with the next generation of in-ice neutrino experiments.

Speaker: Paramita Dasgupta (CCAPP Fellow at Ohio State University)

ARA_5_PA_analysis_Paramita_Dasgupta_TeVPA.pdf

Parallel Session: Particle Physics/Cosmology

Conveners: Anirudh Prabhu (Princeton University), Huangyu Xiao (KICP and Fermilab)

191 An Axion Pulsarscope

Electromagnetic fields surrounding pulsars may source coherent ultralight axion signals at the known rotational frequencies of the neutron stars, which can be detected by laboratory experiments (e.g., pulsarscopes). As a promising case study, we model axion emission from the well-studied Crab pulsar, which would yield a prominent signal at $f \approx 29.6$ Hz regardless of whether the axion contributes to the dark matter abundance. We estimate the relevant sensitivity of future axion dark matter detection experiments such as DMRadio-GUT, Dark SRF, and CASPEr, assuming different magnetosphere models to bracket the uncertainty in astrophysical modeling. For example, depending on final experimental parameters, the Dark SRF experiment could probe axions with any mass $m_a \ll 10^{-13}$ eV down to $g_{a\gamma\gamma} \sim 3 \times 10^{-13}$ GeV$^{-1}$ with one year of data and assuming the vacuum magnetosphere model. These projected sensitivities may be degraded depending on the extent to which the magnetosphere is screened by charge-filled plasma. The promise of pulsar-sourced axions as a clean target for direct detection experiments motivates dedicated simulations of axion production in pulsar magnetospheres.

Speaker: Mariia Khelashvili (Goethe University Frankfurt, Princeton University)

TeVPa_Khelashvili.pdf

192 Simulating Post-Inflationary Axion Misalignment with Adaptive Mesh Refinement

The quantum chromodynamics (QCD) axion, which may explain the absence of a neutron electric dipole moment, arises as the pseudo-Goldstone mode of a spontaneously broken abelian Peccei-Quinn (PQ) symmetry. If the scale of PQ symmetry breaking occurs below the inflationary reheat temperature, then there is a unique axion mass that gives the observed dark matter (DM) abundance. Computing this mass has been the subject of intensive numerical simulations for decades, since the mass prediction informs laboratory experiments that are only able to target narrow mass ranges. In this work we perform the most precise and accurate large-scale simulations to-date of the axion-string network using adaptive mesh refinement to achieve the precision that would otherwise require a static lattice with $262,144^3$ lattice sites. Furthermore, we perform a suite of smaller, systematic simulations to account for axions produced during the QCD phase transition from the string-domain-wall-network collapse and to account for transient aspects of the initial state. These new simulations provide new insights on the dynamics of topological defects and sharpen predictions for the mass of the axion which comprises all the dark matter.

Speaker: Joshua Foster (Massachusetts Institute of Technology)

193 Ultra-light Axions in the Halo Bias

Ultra-light axions with masses $10^{-33} < m_\phi/{\rm eV} < 10^{-22}$ , even as a small fraction of the observed dark matter abundance, may yet produce a visible impact on the cosmology due to their macroscopic quantum scale. Next generation galaxy survey data are poised to challenge this possibility, but in order to do so, all aspects of structure formation in this quasi-linear regime must be accounted for consistently and precisely. This includes modeling not only the effect of these axions on the background cosmology and matter fluctuations, but also on the halo bias that governs the tracers we observe, namely galaxies. In this work we discuss the effect of ultra-light axions on cosmological observables, and present a prescription for computing the growth-induced scale-dependent bias in their presence.

Speaker: Nicholas DePorzio (Boston University)

194 Axion Stars: Mass Functions and Constraints

The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for dark matter substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, axion perturbations on small scales will lead to the formation of axion miniclusters at matter-radiation equality, and subsequently the formation of axion stars. Such compact objects open new windows for indirect searches for axions. We compute the axion star mass function based on recent axion minicluster studies and Bose star simulations. Applying this mass function, we find post-inflation axion-like particles with masses $m_a<3.3 \times 10^{−17}$ eV are constrained by the lack of dynamical heating of stars in ultrafaint dwarfs. We also find that current microlensing surveys are insensitive to QCD axion stars. While we focus on the gravitational detectability of axion stars, our result can be directly applied to other interesting signatures of axion stars, e.g. their decay to photons, that require as input the abundance, mass, and density distribution of axion stars.

Speaker: Jae Hyeok Chang (Fermilab and UIC)

Slides_Chang.pdf

195 Domain walls of string theory axions

The string theory axions can naturally form stable string-domain wall network. The later collapse of the domain walls produce more than one type of axion mass eigenstates apart from gravitational waves.

Speaker: Saurav Das (Washington University in St. Louis)

DAS_TEVPA_2024.pdf

Thursday, August 29

Registration: Breakfast

Plenary Session

196 Astrophysical Lessons from LIGO-Virgo-KAGRA's Black Holes

The LIGO-Virgo-KAGRA Collaboration has observed ~100 gravitational-wave sources to date, including mergers between black holes, neutron stars, and mixed neutron star—black holes. These neutron stars and black holes connect many astrophysical puzzles, including the lives and deaths of stars, cosmic chemical enrichment, and the expansion history of the Universe. I will discuss some astrophysical and cosmological lessons from the latest gravitational-wave discoveries, and discuss what we can expect to learn from the upcoming flood of observations.

Speaker: Maya Fishbach (University of Toronto)

FIshbach-TevPA2024.pdf

197 NANOGrav and Gravitational Waves from the Early Universe

Last year, multiple pulsar timing array collaborations across the globe announced the first evidence of a stochastic background of nHz-frequency gravitational waves. A population of inspiraling supermassive black hole binaries can generate a stochastic background, but there may also be contributions from exotic cosmological sources that formed around the time of the Big Bang. In this talk, I will provide an overview of pulsar timing, present the analyses of the latest 15-year NANOGrav data, and discuss new-physics interpretations.

Speaker: Kimberly Boddy (The University of Texas at Austin)

TeVPA2024-Boddy.pdf

198 Primordial Black Holes and the Early Universe

Primordial black holes, which could have potentially formed after inflation, can have significant implications for the early Universe's history. Such a population of black holes, which may have differing mass and spin, can undergo evaporation due to Hawking radiation at different points in time. In this talk, I will review the potential impact of this evaporation on various cosmological observables, including the creation of matter-antimatter asymmetry, dark radiation, gravitational waves and dark matter.

Speaker: Jessica Turner (Durham University)

TeVPA_2024_v2.pdf

10:30 AM Coffee break

Plenary Session

199 Where Next for Indirect Dark Matter Searches?

I will review current results in indirect searches for dark matter, outline the landscape of upcoming experiments, and survey some key scientific goals for indirect detection over the next decade. I will discuss case studies including prospects for theoretical and experimental advances in indirect searches for heavy WIMPs, and possible early-universe signatures of decaying dark matter.

Speaker: Tracy Slayter (MIT)

Slatyer_TeVPA_24.pdf

200 An Update on the Galactic Center Gamma-ray Excess

This talk will review the status of the Galactic Center Excess (GCE). Discovered fifteen years ago in Fermi data, the GCE appears almost exactly as WIMP dark matter annihilations were predicted to emerge in gamma rays. Despite this and the fact that the excess is seen at high significance, its exact nature remains unclear. I will discuss the status of various aspects of the excess that could weigh on whether it is genuinely the first particle signature of dark matter or instead of astrophysical origin. These include the spatial morphology of the excess and the robustness of efforts to identify a point-source origin for the emission, the latter being a direction where machine learning approaches appear particularly promising.

Speaker: Nicholas Rodd (Lawrence Berkeley National Laboratory)

12:40 PM Lunch

Parallel Session: Dark Matter

Conveners: Gordan Krnjaic (The University of Chicago), Jared Barron (Stony Brook University)

201 JWST Lensed quasar dark matter survey: Strongest gravitational lensing limit on the dark matter free streaming length to date

In this talk, I will present recent constraints on the free-streaming DM particle mass from observations of quadruply lensed quasars. Characterizing the population of low-mass dark matter halos, both in terms of their abundances and concentrations allows us to connect to the underlying particle physics of dark matter. The magnifications of strongly lensed quasars provide a probe of the abundance of structure since the relative brightnesses of the images can be perturbed by low-mass halos both in the lens and along the line-of-sight. In this talk, I will present measurements of the relative magnifications of the strongly lensed warm dust emission in a sample of 9 systems measured with JWST MIRI multi-band imaging, which are used to constrain the half-mode mass of the halo mass function. This is the first science result for the JWST GO-2046 program, which will continue for the full 31 lenses. I constrain a WDM model and find an upper limit on the half-mode mass of $10^{7.6} M_\odot$ at posterior odds of 10:1. This corresponds to a lower limit on a thermally produced dark matter particle mass of 6.1 keV. This is the strongest gravitational lensing constraint to date, and comparable to those from independent probes such as the Ly$\alpha$ forest and Milky Way satellite galaxies.

Speaker: Ryan Keeley (UC Merced)

TeVPA2024.pdf

202 Probing the Dark Sector using an Beam Dump Facility at Fermilab in the PIP-II Era

The accelerator complex at Fermilab is currently undergoing improvements which will increase the available beam power to the complex and is known as Proton Improvement Plan-II (PIP-II). The PIP-II Linac is slated for operation near the end of this decade and will be the main proton driver for Fermilab experiments moving forward and provide the beam to LBNF/DUNE. However, the DUNE physics program requires only a fraction of the available protons provided by PIP-II and there are ideas to explore using the excess protons. The Accelerator Complex Enhancement, or ACE, will provide further upgrades in the 2030s in the form of increased power to LBNF along with a replacement for the Fermilab Booster which could also include an accumulator ring. The Fermilab Facility for Dark Matter Discovery (F2D2) is a proposed PIP-II beam dump facility to search for dark sector physics across detector threshold energy scales. F2D2 will have world-leading sensitivity to accelerator-produced dark matter, millicharged particles, and axion-like particles, which are produced in proton collisions with a fixed target. In this talk, I will summarize the physics possible at F2D2, present sensitivities to different dark sector physics and other beyond the Standard Model searches, and discuss the next steps towards realizing a beam dump program at PIP-II.

Speaker: Matthew Toups (Fermi National Accelerator Laboratory)

Toups_TeVPA_F2D2_08292024.pdf

203 Dark matter minihalos from primordial magnetic fields

Primordial magnetic fields (PMFs) can enhance baryon perturbations on scales on small scales. However, a magnetically driven baryon fluid becomes turbulent near recombination, thereby damping out baryon perturbations below the magnetic jeans scale. In this talk, I show that the initial growth in baryon perturbations gravitationally induces growth in the dark matter perturbations, which are unaffected by turbulence and eventually collapse to form $10^{−11}-10^3$ $M_{\odot}$ dark matter minihalos. If the magnetic fields purportedly detected in the blazar observations are PMFs generated by phase transitions, then such PMFs could potentially produce detectable dark matter minihalos.

Speaker: Pranjal Ralegankar (SISSA)

tevpa.pdf

204 Constraints of Mixed Warm Dark Matter from Milky Way Satellite Galaxies

Milky Way satellite galaxies include some of the oldest, faintest, and most dark matter dominated stellar systems known. By performing a rigorous census of Milky Way satellite galaxies, we are able to extend previous analyses to present novel constraints on a mixed dark matter scenario that contains both cold and warm dark matter components (CWDM). We use the semi-analytical model SASHIMI to obtain the CWDM subhalo suppression function, allowing us to produce simulated subhalos populations for different CWDM scenarios. We then “paint” satellite galaxies onto the subhalos using a galaxy-halo connection model and compare the resulting satellite population to the observed satellite population from the Dark Energy Survey and Pan-STARRS1 to obtain constraints on the fractional abundance of warm dark matter (WDM) as a function of the WDM particle mass. In addition to generic thermal CWDM, we also constrain mixed cold dark matter and sterile neutrino models produced by the Shi-Fuller mechanism. We also briefly describe the potential of future surveys to increase the completeness of the Milky Way satellite census and tighten constraints on mixed dark matter scenarios.

Speaker: Chin Yi Tan (The University of Chicago)

TevPA slides.pdf

205 Searching for Dark Matter interactions in the CMB with ACT and SPT

Models of a dark radiation sector with a mass threshold have been shown to ease the two currently outstanding cosmological tensions. In particular, addition of radiation in the early universe can naturally raise $H_0$ by widening the sound horizon at recombination. An additional coupling between the radiation and dark matter at early times induces dark matter scattering at small scales, which helps to lower the clustering amplitude $S_8$. Recently, lensing measurements from data release 6 by the ACT collaboration have provided strong preference within $\Lambda$CDM for a higher value of $S_8$. In this work, we explore the implications of recent CMB measurements from Planck, ACT and SPT for $S_8$ within a model with dark radiation scattering. We find within this model, the data prefer an $S_8$ value near the late universe measurements without the need to implement $S_8$ priors from DES-Y3 and KiDS-1000 measurements. However, we find this comes at a deficit to the model's ability to simultaneously ease the Hubble tension. We comment on future improvements expected from upcoming data releases.

Speaker: Zilu Zhou (New York University)

Zilu_Zhou_tevpa.pdf

206 Probabilistic Inference of the Structure and Orbit of Milky Way Satellites with Semi-Analytic Modeling

Semi-analytic modeling furnishes an efficient avenue for characterizing dark matter halos associated with satellites of Milky Way-like systems, as it easily accounts for uncertainties arising from halo-to-halo variance, the orbital disruption of satellites, baryonic feedback, and the stellar-to-halo mass (SMHM) relation. We use the SatGen semi-analytic satellite generator – which incorporates both empirical models of the galaxy-halo connection as well as analytic prescriptions for the orbital evolution of these satellites after accretion onto a host – to create large samples of Milky Way-like systems and their satellites. By selecting satellites in the sample that match observed properties of a particular dwarf galaxy, we can infer arbitrary properties of the satellite galaxy within the Cold Dark Matter paradigm. For the Milky Way's classical dwarfs, we provide inferred values (with associated uncertainties) for the maximum circular velocity $v_\mathrm{max}$ and the radius $r_\mathrm{max}$ at which it occurs, varying over two choices of baryonic feedback model and two prescriptions for the SMHM relation. While simple empirical scaling relations can recover the median inferred value for $v_\mathrm{max}$ and $r_\mathrm{max}$, this approach provides realistic correlated uncertainties and aids interpretability. We also demonstrate how the internal properties of a satellite's dark matter profile correlate with its orbit, and we show that it is difficult to reproduce observations of the Fornax dwarf without strong baryonic feedback. The technique developed in this work is flexible in its application of observational data and can leverage arbitrary information about the satellite galaxies to make inferences about their dark matter halos and population statistics.

Speaker: Dylan Folsom (Princeton University)

Folsom-Inference_with_Semianalytics.pdf

Parallel Session: Gamma ray astronomy

Conveners: Anastasia Sokolenko, Milena Crnogorcevic (Stockholm University/OKC)

207 Possible jet contribution to the γ-ray luminosity in NGC 1068

Speaker: Silvia Salvatore

SilviaSalvatore.pdf

208 Characterizing the Line of Sight to Gamma-ray Emitting Galaxies

Speaker: Amy Furniss

209 On the distribution of cosmic rays in the Galactic Center region: new insights from H.E.S.S.

Speaker: Justine Devin (CNRS - Montpellier)

DEVIN_TeVPa2024.pdf

210 Looking at Low-Luminosity AGNs under a gamma-ray lens

Speaker: Gunjan Tomar (Raman Research Institute)

211 Deep observations of the starburst galaxy M82 with VERITAS

Speaker: Lab Saha (Center for Astrophysics | Harvard & Smithsonian)

M82_TeVPA2024.pdf

212 Measurement of the proton spectrum from 4 TeV to 200 TeV using H.E.S.S.

Speaker: Benedetta Bruno (ECAP, FAU Erlangen-Nürnberg)

BBruno_TeVPA_2024.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Shiqi Yu (university of utah)

213 Two Watts is All You Need: Enabling In-Detector Real-Time Machine Learning for Neutrino Telescopes Via Edge Computing

The use of machine learning techniques has significantly increased the physics discovery potential of neutrino telescopes. In the upcoming years, we are expecting upgrades of currently existing detectors and new telescopes with novel experimental hardware, yielding more statistics as well as more complicated data signals. This calls for an upgrade on the software side needed to handle this more complex data in a more efficient way. Specifically, we seek low power and fast software methods to achieve real-time signal processing, where current machine learning methods are too expensive to be deployed in the resource-constrained regions where these experiments are located. We present the first attempt at and a proof-of-concept for enabling machine learning methods to be deployed in-detector for water/ice neutrino telescopes via quantization and deployment on Google Edge Tensor Processing Units (TPUs). We design a recursive neural network with a residual convolutional embedding and adapt a quantization process to deploy the algorithm on a Google Edge TPU. This algorithm can achieve similar reconstruction accuracy compared with traditional GPU-based machine learning solutions while requiring the same amount of power compared with CPU-based regression solutions, combining the high accuracy and low power advantages and enabling real-time in-detector machine learning in even the most power-restricted environments.

Speaker: Miaochen Jin (Harvard University)

TeVPa_2024_Talk_Miaochen_Jin.key

TeVPa_2024_Talk_Miaochen_Jin.pdf

214 Orbital Compton-Getting Dipole with IceCube Cosmic-Ray Muons

The Compton-Getting effect — an apparent dipolar anisotropy of cosmic rays generated by Earth's orbital motion around the Sun — serves as a known calibration source for cosmic-ray anisotropy studies. The amplitude of the Compton-Getting dipole depends on both the orbital speed and the mean spectral index of the cosmic-ray flux. It therefore provides an indirect method for studying the energy spectrum of cosmic rays. This work will report on a preliminary analysis of muon data collected by IceCube in the 10 TeV to 100 TeV range.

Speaker: Juan Carlos Díaz Vélez (University of Wisconsin - Madison)

Orbital Compton-Getting vs Energy.pdf

215 Investigating Cosmic Ray Anisotropy with IceTop Surface Array.

Abstract: In this work, we present preliminary results from our analysis of cosmic-ray showers collected by the IceTop surface array, with a focus on studying cosmic ray anisotropy. By leveraging enhanced statistical power and improved Monte Carlo event simulations, we investigate cosmic ray anisotropy across four energy ranges, from approximately 100 TeV to 10 PeV. This analysis enables us to measure the cosmic ray anisotropy in the Southern Hemisphere at higher energies than previous IceTop analyses. Our findings open avenues for future exploration of potential correlations between arrival direction anisotropy, energy spectrum, and the chemical composition of the cosmic-ray flux.

Speaker: Rasha Abbasi (Loyola University Chicago)

216 Status and Future Plans for IceAct at the IceCube Neutrino Observatory

Abstract: IceAct is an array of compact imaging air Cherenkov telescopes acting as a sub-detector of the IceCube Neutrino Observatory. The telescopes are optimized to operate in the harsh environmental conditions of the geographic South Pole. Since 2019, the first two IceAct telescopes have been operating in a stereoscopic configuration in the center of IceCube’s surface detector, IceTop, which has resulted in three years of data in a coincident data configuration. Presently, IceAct is undergoing a field of view upgrade to a fly’s eye configuration, as a prototype for operations with IceCube-Gen2. In this IceAct-Fly’sEye upgrade, each original upward-facing telescope will be surrounded by six new telescopes, each angled off the zenith, which will expand the field of view from ∼12◦ to ∼36◦. Here, we will review the performance and detector operations of the telescopes since 2019, and discuss plans for the IceAct-Fly’sEye upgrade.

Speaker: Arun Vaidyanathan (Marquette University)

217 Search for neutrino emission from Compton Thick AGN with IceCube

The production of high-energy neutrinos, accompanied by a flux of high-energy gamma rays, is attributed to hadronic interactions within cosmic accelerators. Besides TXS 0506+056, no other gamma-ray sources have been identified as neutrino emitters. Instead, sources opaque to gamma rays are emerging as the most likely source of IceCube neutrinos. Active Galactic Nuclei (AGN) with obscured nuclei fit this picture with neutrino emission from NGC 1068 and NGC 4151. Theoretical models of AGN predict that the gamma rays undergo further interactions and cascade down into MeV gamma rays or hard X-rays. This is supported by the observed excess of neutrinos from hard X-ray-detected AGN. Compton-thick AGN are highly obscured from the presence of dense gas, dust and photons that act as targets for interactions making them potential emitters of neutrinos. We present a search for high-energy neutrinos from a catalog of Compton-thick AGN detected in the hard X-ray regime by NuSTAR using a combined dataset of neutrinos from IceCube.

Speaker: Sreetama Goswami (University of Nevada Las Vegas)

TeVPA2024.pdf

218 Modulation of Ultra-High Energy Neutrino-Induced Radio Signals by Evolving Polar Ice

The polar ice sheets can serve as detection media for neutrinos with energies above 10 PeV. This detection can be achieved by observing Askaryan radiation or measuring in-ice radar echoes from the ionization trail left in the wake of the particle cascade. Ice-based radio neutrino detectors deploy antennas within or near the first 100-150 m of compacted snow, known as the firn layer, where the refractive index increases with depth. Firn density additionally fluctuates over time due to variable surface temperatures and melt events.

We present a simulation study quantifying the variability of in-ice radio signals due to evolving firn density. Glaciological simulations modeled changes in the refractive index profile at Summit Station in Greenland from 1980 to 2021. A radio source was simulated within the ice, and its signal was propagated over a 1 km distance, comparable to the attenuation length of ice. Amplitude fluctuations of signals traversing the firn can reach ~10% or greater. Understanding these effects is vital for accurate reconstruction of neutrino properties.

Additionally, we present preliminary measurements of ice properties and radio propagation at Summit Station as part of the Radar Echo Telescope 2024 summer deployment.

Speaker: Alexander Kyriacou (University of Kansas)

tevpa-talk-alex-kyriacou.pdf

Parallel Session: Particle Physics/Cosmology

Conveners: Aurora Ireland (The University of Chicago), Huangyu Xiao (KICP and Fermilab)

219 Minimal Warm Inflation with a heavy QCD axion

Slow-roll inflation is a successful paradigm. However, even small couplings of the inflaton to other light fields can dramatically alter the dynamics and predictions of inflation. As an example, the inflaton can generically have an axion-like coupling to gauge bosons. Even relatively small couplings will automatically induce a thermal bath during inflation. The thermal friction from this bath can easily be stronger than Hubble friction, altering the usual predictions of any particular inflaton potential. Thermal effects suppress the tensor-to-scalar ratio, r, significantly, and predict unique non-gaussianities. This axion-like coupling provides a minimal model of warm inflation which avoids the usual problem of thermal back-reaction on the inflaton potential. I will discuss a realization of these dynamics in which a heavy QCD axion takes the role of the minimal warm inflaton, and QCD gluons in their unconfined phase comprise the thermal bath, introducing the first model of warm inflation in which the thermal friction emerges directly form coupling the inflaton to Standard Model particles. Exploring hybrid warm inflation as specific example that can fit the current cosmological data, I will show that future collider and beam dump experiments have discovery potential for a heavy QCD axion compatible with the minimal warm inflaton.

Speaker: Kim Berghaus (California Institute of Technology)

MWI_Tevpa_Berghaus.pdf

220 Baryogenesis Relics from Binary Pulsars to Terrestrial Experiments

We explore baryon number violating interactions (BNV) using a simple model involving a charged iso-singlet, color-triplet scalar and a Majorana fermion with interactions in the quark sector. This model has been useful for explaining baryogenesis and the DM-baryon coincidence puzzle. We revisit this model, with chiral perturbation theory as a guide, at the level of baryons and mesons in the dense environments of neutron stars and binary pulsar systems. BNV neutron decays become accessible in this environment where in vacuum they would be kinematically forbidden. By considering several equations of state in binary pulsar candidates, we establish strong constraints on the model parameter space from these decays, and the subsequent scattering of the Majorana fermions, in total amounting to a $\Delta B = 2$ loss in the star. These limits are highly complementary to a number of terrestrial probes, from $n-\bar{n}$ oscillations and di-proton decay to collider searches. Lastly, we suggest a new DM direct detection channel.

Speaker: Adrian Thompson (Northwestern University)

BNV_TeVPa_Thompson.pdf

221 CMB Spectral Distortions from Dark Photon Oscillation

The cosmic microwave background (CMB) spectrum is an extraordinary tool to explore physics beyond the standard model. Due to the exquisite precision of its measurements, it constitutes a natural place to look for small effects due to the hidden universe. In particular, CMB spectral distortions can unveil the existence of dark photons which are kinetically coupled to the standard photon. In this work, we use the COBE-FIRAS dataset to derive self-consistent and robust limits on photon-to-dark-photon oscillations for a large range of dark photon masses, from $10^{-10}$ to $10^{-3}$ eV. We consider in detail the redshift dependence of the bounds, using Green’s function formalism for photon injection/removal to compute the CMB distortions at large redshifts. Our treatment supersedes previous works, which either used Green's function for energy injection/removal rather than photon injection/removal or ignored the redshift dependence of the distortions. The difference between our treatment and previous ones is particularly noticeable in the spectral shape of the distortions, a smoking gun signature for photon-to-dark-photon oscillations. The spectral shape characterization is crucial for future CMB missions along the lines of PIXIE, which could improve the present sensitivity by orders of magnitude, exploring regions of the dark photon parameter space that are otherwise extremely difficult to access.

Speaker: Dr Xucheng Gan (DESY)

TeVPA_2024.pdf

222 Kinetic heating of a neutron star via coherent scatterings with relic neutrinos

We study the kinetic heating of neutron stars due to their coherent scatterings with relic neutrinos via the neutral-current interactions. A neutron star gravitationally attracts relic neutrinos as it travels through the universe, gaining energy from heavy relic neutrinos by scatterings. The heating effect turns out to be possibly detectable by current and future optical/infrared telescopes. In particular, we show that a neutrino of any mass eigenstate with a mass $m_\nu \gtrsim$ a few $\times 100$ keV, which could outperform the current lab bound on the tau neutrino mass, can be probed by using this technique. We also discuss the observability of sterile neutrino dark matter through the neutron star heating effect.

Speaker: Takuya Okawa (Washington University in St. Louis)

TeVPA_Okawa.pdf

223 Electroweak Axion Portal to Dark Matter

Axion-like particles (ALPs) are good candidates for mediators to the dark sector. We explore scenarios in which an ALP mediates interactions between dark matter and electroweak gauge bosons. These models yield testable electromagnetic signals in astrophysical, cosmological, and terrestrial probes. We find promising prospects for both indirect detection and accelerator tests, with interesting parameter space already constrained by current experiments. Our work provides concrete benchmarks for future tests of the electroweak ALP portal.

Speaker: Ngan Nguyen (Johns Hopkins University)

EW_ALP_TeVPA_2024.pdf

224 Stringent constraints on intra-galactic substructure and the primordial power spectrum from ultra-faint dwarf dynamics

In the nightmare scenario, the underlying particle physics of dark matter as
well as our cosmological history could be discerned purely gravitationally by studying
the gravitational substructure that dark matter collapses into. In this talk, I present stringent
limits on this substructure, arising from the non-observation of heat exchange between
substructure contained in ultra-faint dwarfs, and the stars, which would cause the expansion
of the stellar half-light radius to values larger than what is observed. These limits also translate to orders-of-magnitude improvement in limits on the primordial power spectrum down to the kpc scale. These results also have consequences for dark matter self-interactions as well as the lower limit on plausible dark matter mass.

Speaker: Harikrishnan Ramani

TeVPA - Harikrishnan.pdf

3:30 PM Coffee break

Parallel Session: Dark Matter

Conveners: Benjamin Lehmann (MIT), Gordan Krnjaic (The University of Chicago)

225 Cloudy with a Chance of Dark Matter

Dark substructures and compact objects composed entirely of dark matter can hold crucial information regarding the particle nature of dark matter as well as the astrophysical and cosmological processes involved in their formation. We show that if the dark sector couples to the Standard Model photon, then clumps of dark matter between a source star and an observer on Earth could effectively act as "lampshades" and dim starlight. These dimming effects can be searched for in observational surveys which observe the brightness of stars as a function of time, such as microlensing surveys. By considering the EROS-2 and OGLE surveys, we demonstrate how dimming effects could be complementary probes for extended structures of dark matter.

Speaker: Leo Kim (Queen's University)

CloudyDM.pdf

226 Disruption of Dark Matter Minihalos by Successive Stellar Encounters

Scenarios such as the QCD axion with the Peccei-Quinn symmetry broken after inflation predict an enhanced matter power spectrum on sub-parsec scales. These theories lead to the formation of dense dark matter structures known as minihalos, which provide insights into early Universe dynamics and have implications for direct detection experiments. We examine the mass loss of minihalos during stellar encounters, building on previous studies that derived formulas for mass loss and performed N-body simulations. We propose a new formula for the mass loss that accounts for changes in the minihalo profile after disruption by a passing star. We also investigate the mass loss for multiple stellar encounters. We demonstrate that accurately assessing the mass loss in minihalos due to multiple stellar encounters necessitates considering the alterations in the minihalo's binding energy after each encounter, as overlooking this aspect results in a substantial underestimation of the mass loss. We further use a Monte Carlo approach to compute the stellar-disrupted mass function of a population of minihalos in the Milky Way galaxy and find that the present-day disrupted mass function is significantly more suppressed when we take into account this extra destructive nature of multiple stellar encounters.

Speaker: Ian DSouza (University of Canterbury)

TeVPA Presentation - Ian DSouza.pdf

TeVPA Presentation - Ian DSouza.pptx

227 Simulating Atomic Dark Matter in Dwarf Galaxies: The Impact of Dark Dissipation on Galactic Scales

Dark sector theories naturally lead to multi-component scenarios for dark matter where a sub-component can dissipate energy through self-interactions, allowing efficient dark cooling within galaxies. In this talk, I'll present the first cosmological hydrodynamical simulations of dwarf galaxies where the majority of dark matter is collisionless Cold Dark Matter (CDM), but a sub-component (~6%) is strongly dissipative minimal Atomic Dark Matter (ADM). The simulations demonstrate that the addition of even a small fraction of dissipative dark matter can significantly impact galactic evolution. ADM gas with roughly Standard-Model-like masses and couplings can cool efficiently and gravitationally collapse. These effects can significantly enhance the central densities of dwarf galaxies and alter their internal kinematics and their orbital properties around Milky Way-mass galaxies. As a result, observations of dwarf galaxies such as with Rubin and Roman will provide stringent constraints on such dissipative dark sector models.

Speaker: Sandip Roy (Princeton University)

Sandip_Roy_TeVPA_2024.key

Sandip_Roy_TeVPA_2024.pdf

228 Probing atomic dark matter with the high-redshift UV luminosity function

Atomic dark matter is a dark sector model including two fermionic states oppositely charged under a dark U(1) gauge symmetry, which can result in rich cosmological signatures. I discuss recent work using cosmological n-body simulations to investigate the impact of an atomic dark matter sector on observables such as the galactic UV luminosity function at redshifts >10, and consider the constraining power of recent JWST observations for this model.

Speaker: Jared Barron (Stony Brook University)

BarronJared_TeVPA2024.pdf

229 Probing Atomic Dark Matter with the Lyman Alpha Forest

Atomic dark matter (ADM) is a simple extension to the Standard Model that is motivated by considerations in both particle and astrophysics. ADM can alter structure formation on a variety of astrophysical scales due to the presence of dark baryon acoustic oscillations, and its ability to dissipate energy through cooling mechanisms. While previous work has begun to constrain the ADM parameter space using cosmological observations and late time galactic simulations, the intermediate redshifts are largely unexplored. In this talk I present ongoing work investigating how ADM could be probed and constrained from Lyman Alpha forest observations, utilising cosmological hydrodynamical simulations of the ADM.

Speaker: Caleb Gemmell (University of Toronto)

caleb_gemmell_TeVPA_24.pdf

230 A Systematic EFT Approach to SIDM and Detection Prospects Using Stellar Streams

If dark matter has strong self-interactions, future astrophysical and cosmological observations, together with a clearer understanding of baryonic feedback effects, might be used to extract the velocity dependence of the dark matter scattering rate. To interpret such data, we should understand what predictions for this quantity are made by various models of the underlying particle nature of dark matter. In this talk, we systematically compute this function for fermionic dark matter with light bosonic mediators of vector, scalar, axial vector, and pseudoscalar type. We do this by matching to the nonrelativistic effective theory of self-interacting dark matter and then computing the spin-averaged viscosity cross section nonperturbatively by solving the Schrodinger equation, thus accounting for any possible Sommerfeld enhancement of the low-velocity cross section. In the pseudoscalar case, this requires a coupled-channel analysis of different angular momentum modes. We find, contrary to some earlier analyses, that nonrelativistic effects only provide a significant enhancement for the cases of light scalar and vector mediators. Scattering from light pseudoscalar and axial vector mediators is well described by tree-level quantum field theory.

We end by discussing the potential of using stellar streams as detectors of low-mass dark substructure, where self-interactions can have pronounced effects. In particular, we will focus on the cold dark matter case first in an effort to establish a baseline of the features created in stellar streams by low-mass dark substructure. This baseline will in turn set the stage for a more detailed study of the self-interacting dark matter parameter space.

Speaker: Aditya Parikh (Stony Brook University)

Stream_Subhalos_TeVPA2024_Aditya_Parikh.pdf

Parallel Session: Gamma ray astronomy

Conveners: Amy Furniss, Anastasia Sokolenko

231 Envisioning the Future of Gamma-Ray Astronomy in Space: Overview of NASA's FIG SAG Effort

Speaker: Milena Crnogorcevic (Stockholm University/OKC)

MC_TeVPA_2024.pdf

232 Exploring the Gamma-Ray Emission From Young Core-Collapse Supernovae, and their Detectability with the Cherenkov Telescope Array

Speaker: Vikram Dwarkadas (The University of Chicago)

vdwarkadas_sngamma.pdf

233 Detection of OP313 at z=0.997 with LST-1: the most distant VHE blazar to date

Speaker: Mireia Nievas Rosillo (IAC)

OP313_google_slides

OP313_TeVPA2024.pdf

234 LST-1 follow-up of the exceptionally bright gamma-ray burst GRB 221009A

Speaker: Kenta Terauchi (Kyoto University)

tevpa_2024_grb221009a_v3.pdf

235 Study of the variable VHE gamma-ray emission of bright AGN with LST-1

Speaker: Ryuji Takeishi (Institute for Cosmic Ray Research, University of Tokyo)

Takeishi_TeVPa2024_v3_2.pdf

Parallel Session: HE Astro / Gravitational Waves

Conveners: Ariane Dekker (The University of Chicago), Dimitrios Kantzas (LAPTh/CNRS)

236 Signature of vector dark matter in NANOGrav

The angular correlation of pulsar residuals observed by NANOGrav and other pulsar timing array (PTA) collaborations show evidence in support of the Hellings-Downs correlation expected from stochastic gravitational wave background (SGWB).
In this talk, I will give a non-gravitational wave explanation of the observed pulsar timing correlations as caused by an ultra-light gauge boson dark matter (ULDM). In this scenario, the oscillations of the pulsars are due to their interaction with a ULDM background. Apart from the time delay due to this oscillation, there is an associated Doppler time delay as the signal approaches the earth. Finally, I will demonstrate a comparative analysis between our ULDM scenario, and the stochastic gravitational wave background (SGWB), as well as the SGWB with Shapiro time delay hypotheses.

Speaker: ARPAN HAIT (Indian Institute of Technology Kanpur)

237 Probing the origin of astrophysical neutrinos and ultra-high energy cosmic rays using VERITAS and multiwavelength observations of TXS 0506+056

Cosmic rays can be accelerated both in a source or in intergalactic space, producing gamma rays and neutrinos. Furthermore, all cosmic rays that escape a source can potentially initiate particle cascades through interactions with the background radiation fields such as the cosmic-microwave background and the extragalactic background light. In September 2017, a high-energy neutrino event detected by IceCube (IceCube-170922A) was associated, at the 3σ level, with a gamma-ray flare from the blazar TXS 0506+056. This multi-messenger association remains, as per today, the most significant photon-neutrino association ever observed. Here we report on a new search for proton cascade emission in TXS 0506+056, using a combined data set from the Fermi Large Area Telescope and VERITAS. We compare the gamma-ray spectrum and neutrino observations with the predictions of cosmic-ray induced cascades in intergalactic space. We also apply a full statistical analysis to jointly determine the best-fit parameters of a proton emission spectrum describing the data and derive constraints on the proton escape luminosity, using state-of-the-art Monte Carlo simulations.

Speaker: Atreya Acharyya (University of Southern Denmark)

TXS_TeVPA_1.pdf

238 Particle acceleration and production of TeV-PeV neutrinos in magnetized PNS winds

While nuclei lighter than Fe are fused over the course of typical stellar evolution, about half of the heavier elements are created through the rapid neutron capture process (r-process). These nuclei are thought to be produced in magnetized outflows from neutron-rich explosive events including compact mergers and core-collapse supernovae. I will discuss the potential of neutrino-driven winds from strongly magnetized and rapidly rotating protomagnetars as plausible sites for r-process nucleosynthesis. As these heavy nuclei can eventually lead to ultra-high energy cosmic rays, we examine the acceleration and survival conditions for these nuclei in these environments. We also model the propagation of these jets within Wolf-Rayet stars and blue/red supergiants. In particular, we analyze the criteria for a successful jet breakout, maximum energy deposited into the cocoon and structural stability of these magnetized jets. We show that high-energy (TeV-PeV) neutrinos can be produced for extended progenitors like blue/red supergiants and estimate the detectability of these neutrinos with upcoming detectors such as IceCube-Gen2.

Speaker: Dr Mukul Bhattacharya (University of Wisconsin - Madison)

TeVPA_MukulB_PNSneutrinos_Aug29.pdf

TeVPA_MukulB_PNSneutrinos_Aug29.pptx

239 Hints for a Supermassive Black Hole Binary at the center of the blazar J1048+7143*

The multi-messenger light curve of the FSRQ J1048+7143 shows simultaneous quasi-periodic oscillations in the gamma-ray, optical and radio wavelengths. While in gamma rays and optical, the flaring structure consists of two subflares, the radio emissions have no such substructures.
We show that these flaring structures are consistent with a supermassive binary black hole at the center of J1048 and are caused by the coupling of the orbit with the spin of the leading jet. With the here presented model, we successfully predicted the timing of the last flare and constrained the mass ratio of the binary, allowing predictions of when it will merge. Finally, we show our model expectation of the characteristic strain of its gravitational wave emission.
*Supported by DFG (MICRO and SFB 1491)

Speaker: Ilja Jaroschewski

TeVPa_Jaroschewski.pdf

240 Jet propagation and shock breakout emission from neutron star merger simulations

Neutron star (NS) mergers are amongst the most promising multimessenger sources in the Universe, as demonstrated by the coincident detection of gravitational waves (GWs) with multi-wavelength electromagnetic (EM) radiation for GW170817. Although it is well-known that short gamma-ray bursts (GRBs) can originate from relativistic jets launched by NS merger remnants, there are still uncertainties about the exact nature of such a remnant: where is it a promptly formed black hole (BH), a hypermassive NS that later collapses to a BH, or a stable NS. The engine properties, in particular the jet launching mechanism, can affect the jet evolution and their observable signatures. In this work, we investigate the propagation of jets through realistic NS merger ejecta modeled through General-Relativistic Hydrodynamic (GRHD) simulations. We construct a semi-analytical jet+cocoon propagation model and examine the conditions under which these successfully break out from the ejecta. We calculate the EM emission associated with the shock breakout and compare various NS merger simulations with different microphysics or binary configurations with the gamma-ray observational data from GW170817.

Speaker: Eduardo Gutierrez (The Pennsylvania State University)

Gutierrez_TeV24.pdf

241 Multi-messenger emissions from magnetar remnants of binary neutron star mergers

Binary neutron-star (BNS) mergers are accompanied by multi-messenger
emissions, including gravitational wave (GW), neutrino, and
electromagnetic (EM) signals. Some fraction of BNS mergers may result in a
rapidly spinning magnetar as a remnant, which can enhance both the EM
and neutrino emissions. In this talk, I will discuss
the possible neutrino and EM signatures from such systems. I will also discuss the possibility and prospects of performing GW-triggered
stacking searches for high-energy neutrinos from such sources at IceCube-Gen2, using the next generation of GW detectors like Einstein Telescope and Cosmic Explorer.

Speaker: Mainak Mukhopadhyay (The Pennsylvania State University)

mainak_tevpa_2024.pdf

Parallel Session: Neutrino Astrophysics

Conveners: Bei Zhou (Fermilab & KICP), Qinrui Liu (Queen's University)

242 The TRIDENT Deep-sea Neutrino Telescope

Cosmic rays were discovered over a century ago, but the sources of the highest energy components remain unknown. Next-generation neutrino telescopes with significantly improved sensitivity are needed to identify the sources of the diffuse astrophysical neutrinos detected by IceCube, and help decipher the origin of high-energy cosmic rays. The TRopIcal DEep-sea Neutrino Telescope (TRIDENT) will cover approximately 8 km³ of seawater with digital optical modules positioned 3.5 km deep in the western Pacific Ocean. Utilizing advanced photon-detection technology and its large size, TRIDENT aims to observe the IceCube steady source candidate NGC 1068 at 5σ within one year of operation. This sensitivity will enable new insights into the origins of cosmic rays and probe fundamental physics over astronomical distances. This presentation covers the experiment's design, current status, and future prospects, with a pilot project involving ten strings for a technology demonstration scheduled for 2026.

Speaker: Donglian Xu (Tsung-Dao Lee Institute)

TRIDENT_Status_TeVPA2024_Xu.pdf

243 Status of the Trinity PeV Neutrino Observatory

The Trinity Observatory is a proposed UHE-neutrino detector with a core-energy range of $10^6$ GeV-$10^{10}$ GeV, bridging the observational gap between IceCube and UHE radio detectors. It is a system of 60-degree wide field-of-view air-shower imaging telescopes that detect Earth-skimming tau neutrinos from mountain tops. Trinity's primary science objectives are the extension of the IceCube measured neutrino flux to ultrahigh energies, AGN physics, and detecting cosmogenic neutrinos. Trinity will provide critical measurements to study flavor physics and neutrino cross-sections at energies that are out of reach for accelerators. I present the project's status, focusing on the Trinity Demonstrator. This 1 square meter air-shower imaging telescope has been operating on Frisco Peak, Utah, since October 2023 to demonstrate the technology and understand potential backgrounds. In addition, I discuss the discovery potential of diffuse and source UHE neutrinos with the Demonstrator, one Trinity telescope, and the completed system.

Speaker: Nepomuk Otte

TrinityAtTevPA2024.pdf

244 Improved directional uncertainties for IceCube realtime alerts

A primary science goal of the IceCube Neutrino Observatory is the detection of high-energy neutrinos from astrophysical sources. One way to facilitate such discoveries is IceCube's realtime program: IceCube issues alerts in real time for specific categories of high-energy events, thus allowing rapid follow up by the multimessenger community. As an example, follow-up observations initiated by the alert IC170922A found a flaring blazar, TXS 0506+056, in the direction of the alert, ultimately leading to the first astrophysical source detected by IceCube. However, the construction of directional uncertainty contours has historically been inconsistent across individual event reconstructions, often leading to over- or under-coverage. Ultimately, accurate directional uncertainties are crucial for multimessenger follow-ups, while also affecting the interpretation of any discovered associations. In this talk, several updates to the reconstruction model are discussed, based on the tremendous progress made recently towards a refined understanding of the ice. Along with other optimizations, these lead to more consistent likelihood spaces across different events in the realtime stream.

Speaker: Tianlu Yuan (UW Madison)

tevpa24.pdf

245 Probing the Cross Correlation of IceCube Neutrinos with Tracers of Large Scale Structure

The IceCube Neutrino Observatory has observed a diffuse flux of astrophysical neutrinos of so far unknown origin. The absence of strong individual neutrino sources suggests an extragalactic population of dim sources. Although individual neutrino sources may be faint, the population may trace the underlying large scale matter distribution. In this work, we present a search for the origin of astrophysical neutrinos using the two-point cross correlation, a widely used method in cosmology for characterizing correlations between source catalogs. We perform a cross-correlation of more than 10 years of track-like events from IceCube with a galaxy catalog derived from the WISE and 2MASS data that identifies more than 1.2 million nearby galaxies with redshift less than z<0.4. The cross-correlation has the potential to constrain emission of neutrinos from the local universe and possibly provide evidence for the origin of the diffuse neutrino population.

Speaker: David Guevel (University of Wisconsin, Madison)

IceCube-Cross-Correlation-TeVPA.pdf

246 The very-high-energy neutrino diffuse emission and the contribution of sources to the IceCube and ANTARES measurements

We calculate the very-high-energy diffuse flux of neutrinos produced by the hadronic interactions of cosmic rays (CR) with the gas contained in the Galactic disk. We compare our results with recent neutrino observational data in the TeV energy range. Namely, we perform a comparison of our predictions with the recent hint for a Galactic neutrino component obtained by ANTARES and the new IceCube measurement of a neutrino diffuse emission from the Galactic disk. We take advantage of recent source population studies to evaluate the contamination of sources to observational determinations of neutrino diffuse emission. By comparing our expectations with IceCube measurement, we constrain the fraction of Galactic TeV gamma-ray sources (resolved and unresolved) with hadronic nature. We finally discuss the constraints that can be obtained on the CR spatial and energy distribution and, hence, on the neutrino diffuse emission.

Speaker: Vittoria Vecchiotti (NTNU)

TeVPa 2024 (neutrini).pdf

247 Neutrinos and gamma-rays from Galaxy Clusters constrained by the upper limits of IceCube

In this work, we have conducted three-dimensional cosmological magnetohydrodynamical (MHD) simulations of the turbulent intracluster medium (ICM) combined with multi-dimensional Monte Carlo simulations of CR propagation for redshifts ranging from $z \sim 5$ to $z = 0$ to study the multi-messenger emission from these sources. We found that when CRs with a spectral index in the range $1.5 - 2.5$ and cutoff energy $E_\mathrm{max} = 10^{16} - 10^{17}$~eV are injected into the system, they make significant contributions to the diffuse background emission of both neutrinos and gamma-rays. In this work, we constrained our the parametric space based on the existing upper limits on neutrino emission from galaxy clusters, obtained by the IceCube experiment.
We find that for CRs injected with spectral indices in the range $2.0 - 2.5$, cutoff energy $E_\mathrm{max} = 10^{16} - 10^{17}$~eV, and power corresponding to $(0.1-1)\%$ of the cluster luminosity, our neutrino flux aligns with the upper limits estimated by IceCube. Additionally, the resulting contribution from clusters to the diffuse $\gamma$-ray background (DGRB) remains significant with values of the order of $ \sim 10^{-5}\, \mathrm{MeV} \, \mathrm{cm}^{-2} \,\mathrm{s}^{-1} \, \mathrm{sr}^{-1}$ at energies above $500$ GeV.

Speaker: Dr Saqib Hussain (Gran Sasso Science Institute - GSSI, L'Aquila, Italy)

Parallel Session: Particle Physics/Cosmology

Conveners: Huangyu Xiao (KICP and Fermilab), Xucheng Gan (DESY)

248 Dark Spiky Primordial Black Holes

Recent observations of black holes in two nearby low-mass X-ray binaries have indicated the possible presence of dark matter density spikes. While the evidence is compelling, one issue with this interpretation is that light black holes formed from stellar collapse are not expected to form dark matter spikes, and so it is unclear how the stellar-mass black holes in these binaries could have acquired such features. Since primordial black holes are expected to form ultra-dense dark matter mini-spikes, in this talk we explore the possibility that these black holes may actually be primordial in origin.

Speaker: Dr Aurora Ireland (The University of Chicago)

TeVPA 2024.pdf

249 Building Dark Structure Before Big Bang Nucleosynthesis

I present a novel mechanism for creating primordial black holes and dark MACHOs. A heavy dissipative dark sector can come to dominate the universe, creating an early matter dominated era prior to Big Bang Nucleosynthesis (BBN). At this time the dark matter can form halos which persist after the phase transition back to radiation domination, and slowly collapse at late times. This leads to the late time formation of dark MACHOs and subsolar mass primordial black holes. A possible consequence of this model is the present day high temperature evaporation of primordial black holes.

Speaker: Melissa Diamond (Queen's University)

darkstarsshort.pdf

250 A Ratio Preserving Approach to Cosmological Concordance

Cosmological observables are particularly sensitive to key ratios of energy densities and rates, both today and at earlier epochs of the Universe. Well-known examples include the photon-to-baryon and the matter-to-radiation ratios. Equally important, though less publicized, are the ratios of pressure-supported to pressureless matter and the Thomson scattering rate to the Hubble rate around recombination, both of which observations tightly constrain. Preserving these key ratios in theories beyond the $\Lambda$ Cold-Dark-Matter ($\Lambda$CDM) model ensures broad concordance with a large swath of datasets when addressing cosmological tensions. We demonstrate that a mirror dark sector, reflecting a partial $\mathbb{Z}_2$ symmetry with the Standard Model, in conjunction with percent level changes to the visible fine-structure constant and electron mass which represent a \textit{phenomenological} change to the Thomson scattering rate, maintains essential cosmological ratios. Incorporating this ratio preserving approach into a cosmological framework significantly improves agreement to observational data ($\Delta\chi^2=-35.72$) and completely eliminates the Hubble tension with a cosmologically inferred $H_0 = 73.80 \pm 1.02$ km/s/Mpc when including the S$H_0$ES calibration in our analysis. While our approach is certainly nonminimal, it emphasizes the importance of keeping key ratios constant when exploring models beyond $\Lambda$CDM.

Speaker: Kylar Greene (University of New Mexico)

251 Neutrinos in Lake Geneva: Measuring the LHCb Forward Neutrino Flux with Large-Scale Detectors

This work investigates the physics potential of hypothetical large-scale detectors observing the interactions of neutrinos produced in proton-proton collisions at the LHC. We focus on the LHCb interaction point, as the forward neutrino flux from this location passes through Lake Geneva before exiting the Earth's surface. This offers two interesting possibilities: (1) a long pipe-like detector deployed within Lake Geneva, and (2) a large panel-based detector deployed on the Earth's surface. The former can leverage the large active volume enabled by the lake environment to collect a large dataset of all-flavor neutrino interactions within the detector, while the latter can leverage the long range of TeV-scale muons to collect a large dataset of muon neutrino interactions in the surrounding bedrock. One could also perform a coincidence measurement of muon neutrinos interacting in the lake-based detector and producing muons that are then observed in the surface-based detector. We estimate the event rates using a custom Monte Carlo simulation and show that these detectors can pin down the charm hadron contribution to the forward neutrino flux. Such a measurement would significantly constrain existing uncertainties on the prompt atmospheric neutrino flux, an important and poorly understood background to astrophysical neutrino searches at current and next-generation neutrino telescopes.

Speaker: Nicholas Kamp (Harvard University)

TeVPA_2024.pdf

Reception

Convener: Galen Tsongas (The University of Chicago)

Friday, August 30

Registration: Breakfast

Plenary Session

252 Quasi-Periodic Eruptions from Star-Disk Collisions in Galactic Nuclei

A small fraction of the stars in galactic nuclei migrate towards the central supermassive black hole (SMBH) via gravitational wave emission, arriving to small scales on low-eccentricity orbits ("extreme mass-ratio inspirals"; EMRIs). If a gaseous accretion disk suddenly forms around the SMBH during this gradual inspiral (e.g. by an independent tidal disruption event), then twice-per-orbit periodic collisions are expected to occur between the star and the disk. Each time the star passes through the disk, it shocks and ejects hot debris above and below the midplane, powering a luminous burst of hard radiation. I will argue that such star-disk collisions provide a natural explanation for the recently discovered phenomenon of X-ray "quasi-periodic eruptions" (QPE) in low-mass galactic nuclei. If this explanation is correct, QPEs offer a new probe of the EMRI populations in galactic nuclei; the structure of radiation-dominated accretion disks; and strong-gravity effects such as apsidal/nodal orbital precession.

Speaker: Brian Metzger (Columbia)

TeVPA_Metzger.pdf

253 Galactic Cosmic Ray Leptons: New Results and Insights from TeV Halos

In recent years, the study of Galactic cosmic ray leptons has advanced significantly, largely due to measurements of absolute fluxes of positrons and electrons by AMS-02, and to the direct measurements of the total lepton flux above TeV energies by DAMPE and CALET. In this talk, we discuss how these results refine our models of cosmic ray propagation and contribute to resolving outstanding questions about the sources of high-energy cosmic rays. Moreover, the observations of TeV halos surrounding pulsars provide crucial insights into the mechanisms of particle acceleration in pulsar wind nebulae and their release in the interstellar medium. By presenting the latest results from high-energy gamma-ray observatories, we explore how these findings contribute to resolving outstanding questions about the sources of high-energy cosmic ray leptons.

Speaker: Carmelo Evoli (Gran Sasso Science Institute)

slides

254 Progress and challenges in measuring the cosmological 21cm signal

The 21cm line from neutral hydrogen is a rare ubiquitous tracer of the cosmic matter distribution, from very high redshift until the present day. The future of large scale structure cosmology -- mapping out the abundance of modes during the cosmic dark ages -- largely depends on getting the 21cm mapping technique to work in other redshift regimes, which has so far proved rather challenging. In this talk, I will summarise recent progress, including strong detections of the signal at low redshift with the MeerKAT telescope, and improved upper limits from the HERA array at higher redshift. I will then review some of the associated challenges, including pointers to recent areas of progress on data analysis methods and possibilities for future experiment building, including in space and on the lunar farside.

Speaker: Phil Bull (JBCA)

Progress and challenges 21cm.pdf

10:30 AM Coffee break

Plenary Session

255 Probing the dark sector with accelerator experiments

Accelerator experiments, both collider and fixed-target, play a pivotal role in probing the dark sector and uncovering the nature of dark matter. This talk will provide an overview of current efforts and future plans in utilizing accelerators to explore a wide range of dark matter candidates, from WIMPs to light dark sector particles. The synergy and complementarity between accelerator experiments and other experimental and observational approaches will be highlighted.

Speaker: Brian Batell (University of Pittsburgh)

Batell-TeVPA.pdf

256 Phases of Particle Dark Matter Production

How was dark matter produced in the early Universe? There is a growing diversity of particle physics models for dark matter, which can be organized by different mechanisms for dark matter production. In this talk I will chart phase diagrams for thermal and nonthermal production of dark matter, highlighting recent developments.

Speaker: Josh Ruderman (NYU)

257 Conference Summary Talk

Speaker: Gianfranco Bertone

TeVPA 2024 Summary.pdf

Closing

1:10 PM Lunch