A HiRes limit on the flux of the cosmogenic neutrinos

The energy flux spectrum of ultra high energy cosmic rays above 50 EeV (1018eV) measured by the High Resolution Fly's Eye (HiRes) experiment suggests the existence of the expected Greisen-Zatsepin-Kuzmin (GZK) suppression. This implies a flux of cosmogenic neutrinos. Tau leptons produced in charged current interactions emerging from the surrounding mountains and the earth crust provide opportunities for HiRes to detect extensive air showers initiated by tau decay products from the interactions of these cosmogenic neutrinos. We generated tau neutrino Monte Carlo events with a modified All Neutrino Interaction SImulation (ANIS) program and simulated the response of HiRes detectors to those events. As no neutrino events are found in the HiRes data, an upper limit of j(E) = (241 · 9)·E· 2 cm· 2s· 1 sr· 1eV· 1 is set for the energy range from 1018eV to 1021eV with a 90% confidence level.