Combining F-Term Hybrid Inflation With a Peccei-Quinn Phase Transition

TL;DR

This paper presents a model combining F-term hybrid inflation with a Peccei-Quinn phase transition, showing how the transition affects inflationary dynamics and reheating, consistent with observational data and avoiding the gravitino problem.

Contribution

It introduces a renormalizable superpotential model linking hybrid inflation with a PQ transition, analyzing their combined effects on cosmology and particle physics.

Findings

The PQ transition significantly alters inflationary dynamics.

The model aligns with current observational data for the spectral index.

Reheat temperature remains low enough to prevent gravitino overproduction.

Abstract

We consider an inflationary model based only on renormalizable superpotential terms in which a superheavy scale F-term hybrid inflation (FHI) 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 FHI with the current observational data we find that, for the central value of the spectral index, the grand unification scale can assume its supersymmetric value for more or less natural values for the remaining 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.