Speaker
Description
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.
