Kahler potentials for the MSSM inflation and the spectral index

TL;DR

This paper investigates how supergravity corrections and the choice of Kahler potentials influence MSSM inflation, particularly affecting the spectral index, and demonstrates that constraints on these potentials are more flexible than previously thought.

Contribution

It extends previous MSSM inflation models by relaxing Kahler potential constraints and analyzing supergravity effects on inflationary predictions.

Findings

Supergravity corrections can slightly modify the spectral index.

Constraints on Kahler potentials are less restrictive when the saddle point location is variable.

Predicted spectral index ranges from 0.92 to 0.94 with corrections.

Abstract

Recently it has been argued that some of the fine-tuning problems of the MSSM inflation associated with the existence of a saddle point along a flat direction may be solved naturally in a class of supergravity models. Here we extend the analysis and show that the constraints on the Kahler potentials in these models are considerably relaxed when the location of the saddle point is treated as a free variable. We also examine the effect of supergravity corrections on inflationary predictions and find that they can slightly alter the value of the spectral index. As an example, for flat direction field values $|\bar{\phi}_0|=1\times10^{-4}M_P$ we find $n\sim0.92 ... 0.94$ while the prediction of the MSSM inflation without any corrections is $n\sim0.92$.