Nonthermal Production of Gravitinos and Inflatinos in the Inflationary Universe

Abstract

The success of primordial nucleosynthesis imposes stringent bounds on the abundance of gravitational relics. This is particularly true for gravitinos, which — for models with gravitationally mediated supersymmetry breaking — are expected to have a mass below the TeV scale and thus to decay only after nucleosynthesis has concluded. We discuss the nonthermal production of gravitinos in models with several chiral fields, to be able to distinguish the mechanisms of supersymmetry breaking and inflation. Our explicit calculations show that the superpartner of the inflaton can be significantly generated. Gravitinos can be produced both at the preheating stage and at the subsequent inflaton/inflatino decay. We verify that this production is well below the nucleosynthesis bound, provided the sector responsible for the present supersymmetry breakdown is weakly (for example, only gravitationally) coupled to the one which drove inflation.