Are ultrahigh energy cosmic rays signals of supersymmetry?

Abstract

We investigate the possibility that cosmic rays of energy larger than the Greisen-Zatsepin-Kuzmin cutoff are not nucleons, but a new stable, massive, hadron that appears in many extensions of the standard model. We focus primarily on the S^0, a uds-gluino bound state. The range of the S^0 through the cosmic background radiation is significantly longer than the range of nucleons, and therefore can originate from sources at cosmoglogical distances.

20 page LaTeX file with 5 PostScript figures included with epsf. Discussion of acceleration mechanisms has been elaborated and some new references have been added. No change in conclusions or figures