Extensive Air Showers from Ultra High Energy Gluinos

We study the proposal that the cosmic ray primaries above the Greisen-ZatsepinKuzmin (GZK) cutoff are gluino-containing hadrons (g̃-hadrons). We describe the interaction of g̃-hadrons with nucleons in the framework of the Gribov-Regge approach using a modified version of the hadronic interaction model QGSJET for the generations of Extensive Air Showers (EAS). There are two mass windows marginally allowed for gluinos: mg̃ < ∼ 3 GeV and 25 < ∼ mg̃ < ∼ 35 GeV. Gluinocontaining hadrons corresponding to the second window produce EAS very different from the observed ones. Light g̃-hadrons corresponding to the first gluino window produce EAS similar to those initiated by protons, and only future detectors can marginally distinguish them. We propose a beam-dump accelerator experiment to search for g̃-hadrons in this mass window. We emphasize the importance of this experiment: it can discover (or exclude) the light gluino and its role as a cosmic ray primary at ultra high energies. PACS numbers: 98.70.Sa, 14.80.-j