A next-to-minimal supersymmetric model of hybrid inflation

We propose a model of inflation based on a simple variant of the NMSSM, called φNMSSM, where the additional singlet φ plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the φNMSSM solves the μ problem of the MSSM via the VEV of a gauge singlet N, but unlike the NMSSM does not suffer from domain wall problems since the offending Z3 symmetry is replaced by an approximate Peccei-Quinn symmetry which also solves the strong CP problem, and leads to an invisible axion with interesting cosmological consequences. The PQ symmetry may arise from a superstring model with an exact discrete Z3×Z5 symmetry after compactification. The model predicts a spectral index n=1 to one part in 1012.