What Can we learn from Cosmic Rays?
Abstract
Description
Ultra high energy cosmic rays (UHECR) pose a problem either for particle physics or for astrophysics (or for both) by the unexpectedly high number of cosmic ray showers observed with energy above about 5x10^{19}eV, the Greisen-Zatsepin-Kuzmin (GZK) cutoff. Our emphasis is on those possible solutions of the puzzle which assume that ultra high energy neutrinos travel cosmic distances. We present, in detail, a model which is based on a low energy (50 to 100 TeV) transition to a higher than four dimensional string regime. Neutrino-quark cross sections grow exponentially close to the threshold of this new scale because of the fast increase of the density of string states and effectively acquire hadronic strength.
Presented by S. Kovesi-Domokos at the Jophns Hopkins Workshop, "High Eenergy Reactions", Heidelberg 2002
Presented by S. Kovesi-Domokos at the Jophns Hopkins Workshop, "High Eenergy Reactions", Heidelberg 2002