Reheating phase diagram for single-field slow-roll inflationary models

TL;DR

This paper explores how reheating parameters affect inflationary predictions and demonstrates that certain models can fit observational data better when reheating is considered, with implications for future CMB constraints.

Contribution

It introduces a novel analysis of reheating constraints in the $N_{reh}-w_{reh}$ plane from Planck data and shows how reheating influences model viability.

Findings

Reheating constraints can be derived from Planck 2015 data.

Some inflation models fit observations better with reheating effects.

Future CMB experiments will tighten constraints on reheating parameters.

Abstract

We investigate the influence on the inflationary predictions from the reheating processes characterized by the $e$-folding number $N_{\mathrm{reh}}$ and the effective equation-of-state parameter $w_{\mathrm{reh}}$ during the reheating phase. For the first time, reheating processes can be constrained in the $N_{\mathrm{reh}}\!-\!w_{\mathrm{reh}}$ plane from Planck 2015. We find that for Higgs inflation with a nonminimal coupling to gravity, the predictions are insensitive to the reheating phase for current CMB measurements. We also find that the spontaneously broken SUSY inflation and axion monodromy inflation with $\phi^{2/3}$ potential, which with instantaneous reheating lie outside or at the edge of the $95\%$ confidence region in the $n_s\!-\!r$ plane from Planck 2015 TT,TE,EE$+$lowP, can well fit the data with the help of reheating processes. Future CMB experiments would put strong constraints on reheating processes.