Are we seeing magnetic monopole cosmic rays at $E\text{gsim}10^{20}$ eV?

Abstract

We suggest that the highest energy $\text{gsim}10^{20}$ eV cosmic ray primaries may be relativistic magnetic monopoles. Motivations for this hypothesis are twofold: (i) conventional primaries are problematic, while monopoles are naturally accelerated to $E\sim 10^{20}$ eV by galactic magnetic fields; (ii) the observed highest energy cosmic ray flux is just below the Parker limit for monopoles. By matching the cosmic monopole production mechanism to the observed highest energy cosmic ray flux we estimate the monopole mass to be $\text{lsim}10^{10}$ GeV.

Comments: 5 pages, latex, no figures, uses attached espcrc2.sty file; presented at the Dark Matter'96 Conf, UCLA, Febr. 14--16, 1996