Cosmic PeV Neutrinos and the Sources of Ultrahigh Energy Protons

Abstract

The IceCube experiment recently detected the first flux of high-energy neutrinos in excess of atmospheric backgrounds. We examine whether these neutrinos originate from within the same extragalactic sources as ultrahigh-energy cosmic rays. Starting from rather general assumptions about spectra and flavors, we find that producing a neutrino flux at the requisite level through pion photoproduction leads to a flux of protons well below the cosmic-ray data at ~10^18 eV, where the composition is light, unless pions/muons cool before decaying. This suggests a dominant class of accelerator that allows for cosmic rays to escape without significant neutrino yields.

Comments: 10 pages, 7 figures; v2: substantially updated to incorporate new IceCube data and model scenarios; v3: added references, accepted for publication in Physical Review D