  We propose an interpretation of the two neutrino initiated cascade events
with PeV energies observed by IceCube: Ultra-high energy cosmic ray protons (or
Fe nuclei) scatter on CMB photons through the Delta-resonance (the
Berezinsky-Zatsepin process) yielding charged pions and neutrons. The neutron
decays give electron-antineutrinos which undergo neutrino oscillations to
populate all antineutrino flavors, but the electron-antineutrino flux remains
dominant. At 6.3 PeV electron-antineutrino energy their annihilation on
electrons in the IceCube detector is enhanced by the Glashow resonance (the
W-boson) whose decays can give the PeV showers observed in the IceCube
detector. The two observed showers with ~1 PeV energies would need to be from W
leptonic decays to electrons and taus. An order of magnitude higher event rate
of showers at 6.3 PeV is predicted from W to hadron decays. This interpretation
can be tested in the near term. It has significant physics implications on the
origin of the highest energy cosmic rays, since neutrino events and cosmic ray
events likely share a common origin.
