New Constraints on Cosmogenic Neutrinos from IceCube Data

Recent research led by Maximilian Meier on behalf of the IceCube Collaboration presents new findings regarding cosmogenic neutrinos, which are produced from interactions between ultra-high-energy cosmic rays and cosmic microwave background photons. This study, titled "Recent cosmogenic neutrino search results with IceCube and prospects with IceCube-Gen2," utilizes 12.6 years of data from the IceCube detector located at the South Pole. The IceCube detector is designed to detect Cherenkov light emitted by charged particles resulting from neutrino interactions in a cubic kilometer of ice.

The research establishes new constraints on the extremely high-energy (EHE) neutrino flux, specifically above 5 million GeV. The results indicate that the all-flavor EHE neutrino flux at 1 EeV is constrained to below approximately 10^{-8} GeV cm^{-2} s^{-1} sr^{-1}. This finding is significant as it probes the nature of cosmic rays beyond the energies associated with resonant photo-pion production, known as the Greisen-Zatsepin-Kuzmin (GZK) cutoff.

Looking forward, the upcoming IceCube-Gen2 project aims to enhance the detection capabilities for EHE neutrinos by incorporating radio antennas into the existing in-ice detector. This expansion is expected to increase the effective detection volume significantly, allowing for the observation of fluxes that are about 1.5 orders of magnitude smaller than current limits at 1 EeV.

The implications of these findings are crucial for understanding cosmic rays and their interactions, which play a vital role in astrophysical phenomena. The study contributes to the ongoing efforts to unravel the mysteries of the universe's most energetic particles and their origins.