Affleck-Dine baryogenesis and gravitino dark matter

Abstract

Affleck-Dine baryogenesis in models where the gravitino is both the lightest supersymmetric particle and the dark matter candidate is investigated. For a high enough reheating temperature to produce sufficient gravitinos by thermal processes, the observed baryon asymmetry can be explained by Affleck-Dine baryogenesis as well as thermal leptogenesis. On the other hand, if the reheating temperature is not high enough, most of the gravitinos must be produced by the decay of the next-to-lightest supersymmetric particle (NSP). Particularly, in the case where Q-balls cannot survive the evaporation, the gravitino number density is given by the NSP's thermal relic density. Interestingly, if Q-balls survive, they can be a source of gravitinos via the NSP decay. Then, we could find a new cosmological interesting region in parameter space because the gravitino number density does not relate to the NSP's thermal relic density.