Spectral Index and Non-Gaussianity in Supersymmetric Hybrid Inflation

TL;DR

This paper explores a supersymmetric hybrid inflation model with two inflaton fields, analyzing spectral index and non-Gaussianity, and how supergravity corrections influence inflation dynamics and observable predictions.

Contribution

It introduces a two-field supersymmetric hybrid inflation model with controlled spectral index and potential for large non-Gaussianity, highlighting the role of supergravity corrections.

Findings

The model achieves a spectral index n_s ≈ 0.96 consistent with WMAP7.

Supergravity corrections influence the inflaton mass ratio and inflation dynamics.

Potential for large non-Gaussianity in the two-field inflation scenario.

Abstract

We consider a supersymmetric hybrid inflation model with two inflaton fields. The superpotential during inflation is dominated by W=(\kappa S+\kappa' S')M^2, where S, S' are inflatons carrying the same U(1)_R charge, \kappa, \kappa' are dimensionless couplings, and M (\sim 10^{15-16} GeV) is a dimensionful parameter associated with a symmetry breaking scale. One light mass eigenstate drives inflation, while the other heavier mass eigenstate is stuck to the origin. The smallness of the lighter inflaton mass for the scalar spectral index n_s\approx 0.96, which is the center value of WMAP7, can be controlled by the ratio \kappa'/\kappa through the supergravity corrections. We also discuss the possibility of the two field inflation and large non-Gaussianity in this setup.