Extreme-energy cosmic rays: hints to new physics beyond the standard model?

Abstract

The observed extreme energy cosmic ray (EECR) events above 10(20) eV are difficult to explain within tile standard scenario of origin of cosmic rays in which charged particles are accelerated in magnetized shocks in powerful astrophysical sources and their interaction is governed by the Standard Model of particle physics. Several ideas involving possible new physics beyond the Standard Model have been suggested in order to explain these events. Here we review some of the major proposed new physics solutions of EECR origin and discuss how the up-coming and future EECR experiments will be able to probe some possible forms of physics beyond the Standard Model otherwise not possible in terrestrial accelerators.