Possible astrophysical signatures of heavy stable neutral relics in supergravity models

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 range103GeV<~mX <~1011 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 103 GeV<~mx<~107 GeV, astrophysical bounds from a 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.