Strongly Interacting Neutrinos and the Highest Energy Cosmic Rays

Cosmic rays of energies larger than the Greisen–Zatsepin–Kuzmin (GZK) cutoff may be neutrinos if they acquire strong interactions due to a “precocious unification” of forces. A scenario for this to happen is outlined. There is no contradiction with precision measurements carried out at LEP and SLAC. Observable consequences at LHC and future neutrino detectors are discussed. PACS 13.85.T, 13.15, 14.60.S A substantial number of cosmic ray events has been detected in which the primary energy appears to exceed the Greisen-Zatsepin-Kuzmin (GZK) cutoff, see e.g. [1, 2, 3, 4] and Szabelski’s recent review [5]. The onset of the GZK cutoff itself is somewhat uncertain: the energy of the rapid turnover of the spectrum depends on several details (for instance, on the injection spectrum, etc. ), see ref. [6] for a modern treatment. Nevertheless, it is unlikely that all the events reported can be explained by fluctuations in the shower development. ∗E-mail: [email protected]