Gravity waves and gravitino dark matter in μ-hybrid inflation

Abstract

We propose a novel reformulation of supersymmetric (more precisely μ-) hybrid inflation based on a local U(1) or any suitable extension of the minimal supersymmetric standard model (MSSM) which also resolves the μ problem. We employ a suitable Kahler potential which effectively yields quartic inflation with non-minimal coupling to gravity. Imposing the gravitino Big Bang Nucleosynthesis (BBN) constraint on the reheat temperature (Tr≲106 GeV) and requiring a neutralino LSP, the tensor to scalar ratio (r) has a lower bound r≳0.004. The U(1) symmetry breaking scale lies between 108 and 1012 GeV. We also discuss a scenario with gravitino dark matter whose mass is a few GeV