A next-to-minimal supersymmetric model of hybrid inflation

We propose a model of inflation based on a simple variant of the NMSSM, called phi NMSSM, where the additional singlet phi plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the phi NMSSM solves the mu 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 Z(3) 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 Z(3) x Z(5) symmetry after compactification. The model predicts a spectral index n = 1 to one part in 10(12). (C) 1998 Published by Elsevier Science B.V.