Perturbative Reheating in the Mixed Higgs-$R^2$ Model

TL;DR

This paper analyzes the role of perturbative decay during reheating in the mixed Higgs-$ R^2 $ inflation model, highlighting its impact on reheating duration and temperature, and clarifying the influence of early preheating stages.

Contribution

It provides a detailed study of perturbative reheating in the mixed Higgs-$ R^2 $ model, including effects on reheating temperature and duration, which was previously unexplored.

Findings

Perturbative decay significantly influences the entire reheating process.

The presence of early preheating stages may not alter the final reheating temperature.

Early preheating can affect the number of e-folds during reheating.

Abstract

The preheating process in the mixed Higgs-$ R^2 $ model has been investigated in depth recently, but the analysis of perturbative reheating is still missing. In this paper, we discuss the effect of perturbative decay during (p)reheating in this model. It is shown that perturbative decay can play an important role throughout the whole reheating process. Depending on the model parameters, perturbative decay can affect different stages of the reheating. We study the perturbative reheating with and without the presence of early preheating stage, and calculate the reheating temperature and the duration of the whole perturbative process. We find that the detail of the early preheating stage may not affect the final reheating temperature while it can affect the number of e-folds of reheating.