Implications of the ultrahigh-energy cosmic-ray spectrum observed by the Fly's Eye detector.

Abstract

We discuss the potential implications of the recent results of the Fly's Eye detector on the ultrahigh-energy cosmic-ray spectrum. The data suggest that the observed slope flattening immediately prior to the cutoff appears to be a recoil-proton pileup associated with an ${E}^{\mathrm{\ensuremath{-}}2.5\ifmmode\pm\else\textpm\fi{}.3}$ injection spectrum. We discuss the induced neutrino spectrum and its detectability in Fly's Eye and DUMAND detectors.