Implication of preheating on gravity assisted baryogenesis in $R^2$-Higgs inflation

TL;DR

This paper explores how preheating affects gravity-assisted baryogenesis in $R^2$-Higgs inflation, highlighting the dependence on non-minimal coupling and estimating the baryogenesis scale with improved accuracy.

Contribution

It provides the most precise estimation to date of the gravity-induced baryogenesis scale in $R^2$-Higgs inflation, considering preheating effects and non-minimal coupling.

Findings

Preheating can occur for Higgs, gauge, and Goldstone bosons depending on $\xi_H$.

The preheating temperature determines the baryogenesis scale, approximately $2.2 imes 10^{-5} M_{P}$ for $\xi_H ext{~} 1$.

The study offers the most accurate estimation of the baryogenesis scale in this inflationary scenario.

Abstract

We investigate the impact of preheating on baryogenesis in $R^2$-Higgs inflation. In this scenario, the inclusion of a dimension-six operator ${(R/ \Lambda^2)} B_{\mu\nu} \widetilde{B}^{\mu\nu} $ abundantly generates helical hypermagnetic fields during inflation, leading to a baryon asymmetric Universe at the electroweak crossover. Focusing on the $R^2$-like regime, we first derive the relevant dynamics of preheating using a doubly-covariant formalism. We find that preheating can happen for the Higgs, transverse gauge and Goldstone bosons, however, it is dependent on the value of the non-minimal coupling $\xi_H$ between the Standard Model Higgs field and the Ricci scalar. We identify the preheating temperature to determine the appropriate scale $\Lambda$ for driving baryogenesis, which is around $\Lambda \sim 2.2 \, (2.6) \times 10^{-5}\, M_{\rm P}$ for $\xi_H \sim 1 \, (10)$. Our results represent the most accurate estimation of the scale of gravity induced baryogenesis in $R^2$-Higgs inflation to date. Areas for further improvement are identified.