Consistent cosmology with Higgs thermal inflation in a minimal extension of the MSSM

Abstract

We consider a class of models in which minimal gauged F-term hybrid inflation is coupled renormalisably to the minimal supersymmetric standard model (MSSM), with no extra ingredients; we call this class the "minimal hybrid inflationary supersymmetric standard model" (MHISSM). The singlet inflaton supplies the Higgs mu-term, and allows an exit from inflation to a vacuum characterised by large Higgs vevs. The true ground state is reached after an period of thermal inflation along the Higgs flat direction. The scalar spectral index is reduced from the standard F-term value, to approximately 0.976 in the case where the inflaton potential is dominated by the 1-loop corrections. The reheat temperature following thermal inflation is about 10^9 GeV, solving the gravitino overclosure problem. A Higgs condensate reduces the cosmic string mass per unit length, rendering it compatible with the Cosmic Microwave Background constraints without tuning the inflaton coupling. With the minimal U(1)' gauge symmetry in the inflaton sector, where one of the waterfall fields generates a right-handed neutrino mass, we investigate the Higgs thermal inflation scenario in three popular supersymmetry-breaking schemes: AMSB, GMSB and the CMSSM, focusing on the constraints on the gravitino mass.