XXth International Conference on Neutrino Physics and Astrophysics
D.Semikoz
Upper Limits on Ultra-High Energy Neutrino Fluxes from
Cosmic and Gamma-Ray Data
Applying our recently developed propagation code we review neutrino
fluxes above 10^15 eV in various scenarios and how they are
constrained by current data. We specifically find a new
model-independent upper limit on the cosmogenic neutrino flux produced
by pion production of cosmic rays outside their sources that is
considerably higher than the "Waxman-Bahcall bound". This is easy to
achieve for sources with hard injection spectra and luminosities that
were higher in the past. Such fluxes would significantly increase
chances to observe ultra-high energy neutrinos in experiments which
are currently under construction (such as Pierre Auger Observatory,
HiReS, RICE) or in the proposal stage (such as EUSO, ICECUBE, MOUNT,
Telescope Array).
Based on a paper in preparation with O.Kalashev, V.Kuzmin & G.Sigl