Axino and gravitino dark matter with low reheating temperature

Abstract

Possible discovery of supersymmetric particles in the second run of the LHC accompanied by lack of observation of a dark matter particle in direct searches may point towards dark matter candidates being extremely weakly interacting particles with supersymmetric origin. We focus on two such candidates that are well motivated theoretically, namely the axino and the gravitino. In particular, we derive the lower limits for the reheating temperatures in such scenarios that come from the relic density and the Big Bang Nucleosynthesis constraints. Beside that, the upper limit on the axino dark matter mass is found as a function of the reheating temperature. These issues can be properly treated only when non-instantaneous reheating of the Universe after a period of cosmological inflation is taken into account.