Highest-Energy Cosmic Rays from Fermi-Degenerate Relic Neutrinos Consistent with Super-Kamiokande Results

Relic neutrinos with mass ${0.07}_{-0.04\mathrm{}}^{+0.02\mathrm{}}\mathrm{eV}$, in the range consistent with Super-Kamiokande data, can explain the cosmic rays with energies in excess of the Greisen-Zatsepin-Kuzmin cutoff. The spectrum of ultrahigh energy cosmic rays produced in this fashion has some distinctive features that may help identify their origin. Our mechanism does not require but is consistent with a neutrino density high enough to be a new kind of hot dark matter.