Speaker
Description
Recent measurements of astrophysical neutrinos have expanded our understanding of their nature and origin. However, very little is still known about the astrophysical $\nu/\bar{\nu}$ ratio. The only direct measurement is the recent, single Glashow event at IceCube. Understanding the astrophysical $\nu/\bar{\nu}$ ratio has a bearing on multiple questions, including the astrophysical spectral shape and neutrino production mechanisms. This talk will present a new approach to measuring the astrophysical muon $\nu/\bar{\nu}$ ratio at various energies. It uses inelasticity, the fraction of the initial neutrino energy carried away by the hadronic shower. Inelasticity probes the $\nu/\bar{\nu}$ ratio due to the fact that at energies below roughly 100 TeV, valence quarks dominate in deep inelastic scattering interactions, leading to different neutrino and antineutrino inelasticities and cross-sections. We use 10.3 years of IceCube’s Enhanced Starting Tracks Event Selection (ESTES): starting tracks at energies between 1 TeV and 1 PeV with a self-veto selection that enhances astrophysical event purity in the down-going direction. Additionally, we select regions of high astrophysical purity. Based on this sample and analysis method, we present a projected sensitivity to the astrophysical $\nu/\bar{\nu}$ ratio.
