ACT inflation and its influence on reheating era in Einstein-Gauss-Bonnet gravity

TL;DR

This paper examines how ACT-DR6 data influences inflationary and reheating parameters in scalar-Einstein-Gauss-Bonnet gravity, revealing significant impacts on viable models and reheating conditions compared to Planck data alone.

Contribution

It provides the first detailed analysis of ACT-DR6 data's effects on inflation and reheating in scalar-Einstein-Gauss-Bonnet gravity, highlighting new constraints on reheating parameters.

Findings

ACT data significantly alters inflationary e-fold estimates.

Reheating temperature and equation of state are constrained by combined data.

ACT data disfavors $w_{eff} < 1/3$ during reheating.

Abstract

We investigate the observational viability of non-minimally coupled scalar-Einstein-Gauss-Bonnet (GB) gravity, during inflation and post-inflationary reheating dynamics, from the perspective of the latest ACT-DR6 combined with the Planck 2018 and BAO data. It turns out that the ACT result considerably affects the inflationary e-fold number compared to the case where only Planck 2018 data is taken into account. The viable parameter spaces corresponding to the inflationary ACT-DR6+Planck18+BAO substantially influence the reheating phenomenology via the reheating equation of state ($w_\mathrm{eff}$) and the reheating temperature. In particular, the ACT-DR6+Planck18+BAO data seems to disfavor $w_\mathrm{eff} < 1/3$ during the reheating stage, which is unlike to that of only Planck 2018 case. These reveal how the ACT-DR6 data hits the early universe phenomenology from inflation to reheating in the context of higher curvature like scalar-Einstein-GB theory of gravity.