Limits to gauge coupling in the dark sector of super-heavy dark matter particles from the Pierre Auger Observatory data

Abstract

Assuming that the energy density of super-heavy particles matches that of dark matter observed today, tight constraints on the couplings governing the decay process are presented as a function of the particle mass. These constraints are obtained from the lack of signatures that would be suggestive of decaying super-heavy XX particles in the data of the Pierre Auger Observatory. In particular, instanton-induced decay processes allow us to derive a bound on the reduced coupling constant of gauge interactions in the dark sector: \alpha_X \lesssim 0.09αX≲0.09, for 10^{9} \lesssim M_X/\mathrm{GeV} < 10^{19}109≲MX/GeV<1019. Cosmological aspects for super-heavy dark matter production during the reheating epoch are discussed.