Constraints on K\"ahler moduli inflation from reheating

TL;DR

This paper analyzes K"ahler moduli inflation predictions for spectral tilt, considering reheating effects and post-inflationary history, and compares results with PLANCK data, highlighting the need for exotic reheating scenarios.

Contribution

It introduces a parametrization of reheating effects in K"ahler moduli inflation and assesses compatibility with observational data, including future experiment sensitivities.

Findings

Exotic reheating with $w_{re} > 1/3$ is needed to match PLANCK data.

For canonical reheating ($w_{re} = 0$), the reheat temperature is extremely high.

The model's predictions depend critically on the reheating equation-of-state parameter.

Abstract

We present predictions of the K\"ahler moduli inflation model for the spectral tilt by parametrising the reheating epoch by an effective equation-of-state parameter and the number of e-foldings of reheating; and taking into account the post-inflationary history of the model. This model has an epoch in which the energy density of the universe is dominated by cold moduli particles. We compare our results with data from the PLANCK mission and find that exotic reheating (with effective equation of state $w_{\rm re}$ greater than 1/3) is required to match the observations. For canonical reheating case with $w_{\rm re} = 0$, we deduce $\text{log}_{10}(T_{\rm re}/10^3~ \text{GeV}) \simeq 1190 (n_s - 0.956)$. We also analyse our results in the context of observations being planned for the future and their projected sensitivities.