Description
We consider an inflationary model based only on renormalizable superpotential terms in which a superheavy scale hybrid inflation is followed by a Peccei-Quinn (PQ) phase transition. We show that the field which triggers the PQ phase transition influences drastically the inflationary dynamics and that the Universe undergoes a secondary phase of reheating after the PQ phase transition. Confronting inflation with the current observational data we find that, for the central value of the spectral index, the GUT scale can assume its supersymmetric value for more or less natural values for the model parameters. On the other hand the final reheat temperature after the PQ phase transition turns out to be low enough to avoid the gravitino problem.
