Smooth hybrid inflation in a supersymmetric axion model

TL;DR

This paper demonstrates a natural realization of smooth hybrid inflation within a supersymmetric axion framework, predicting observable axion isocurvature perturbations and a dark matter candidate from non-thermal wino production.

Contribution

It introduces a model where Peccei-Quinn scalar fields drive inflation and produce testable predictions for cosmological perturbations and dark matter.

Findings

Successful inflation reproduces WMAP observations.

Predicts large axion isocurvature perturbations and non-Gaussianity.

Dark matter is explained by non-thermal wino production.

Abstract

We show that the smooth hybrid inflation is naturally realized in a framework of supersymmetric axion model. Identifying the Peccei-Quinn scalar fields as a part of the infaton sector, successful inflation takes place reproducing the amplitude and spectral index of the curvature perturbation observed by WMAP. A relatively large axion isocurvature perturbation and its non-Gaussianity are predicted in our model. The saxion coherent oscillation has a large amplitude and dominates the Universe. The subsequent decay of the saxion produces huge amount of entropy, which dilutes unwanted relics. Winos, the lightest supersymmetric particles in this scenario, are produced non-thermally in the decay and account for dark matter.