Strongly Interacting Astrophysical Neutrinos
  The origin and chemical composition of ultra high energy cosmic rays is still an open question in astroparticle physics. The observed large-scale isotropy and also direct composition measurements can be interpreted as an extragalactic proton dominance above the ankle at about 10^10 GeV. Photopion production of extragalactic protons in the cosmic microwave background predicts a cutoff at about 5x10^10 GeV in conflict with excesses reported by some experiments. In this report we will outline a recent statistical analysis (astro-ph/0506698) of cosmic ray data using strongly interacting neutrinos as primaries for these excesses. 
Markus Ahlers