MSSM flat direction inflation: slow roll, stability, fine tunning and reheating

Abstract

We consider low scale slow roll inflation driven by the gauge invariant flat directions {\bf udd} and {\bf LLe} of the Minimally Supersymmetric Standard Model at the vicinity of a saddle point of the scalar potential. We study the stability of saddle point and the slow roll regime by considering radiative and supergravity corrections. The latter are found to be harmless, but the former require a modest finetuning of the saddle point condition. We show that while the inflaton decays almost instantly, full thermalization occurs late, typically at a temperature $T\approx 10^{7}$ GeV, so that there is no gravitino problem. We also compute the renormalization group running of the inflaton mass and relate it to slepton masses that may be within the reach of LHC and could be precisely determined in a future Linear Collider experiment.