Possible astrophysical signatures of heavy stable neutral relics in supergravity models

Abstract

We consider heavy stable neutral particles in the context of supergravity and show that a gravitationally suppressed inflaton decay can produce such particles in cosmologically interesting abundances within a wide mass range $10^3\mathrm{GeV}\le m_X\le 10^{11}\mathrm{GeV}$. In gravity-mediated supersymmetry breaking models, a heavy particle can decay into its superpartner and a photon-photino pair or a gravitino. Such decays only change the identity of a possible dark matter candidate. However, for $10^3\mathrm{GeV}\le m_X\le 10^7\mathrm{GeV}$, astrophysical bounds from gamma-ray background and photodissociation of light elements can be more stringent than the overclosure bound, thus ruling out the particle as a dark matter candidate.

12 pages