Gauss-Bonnet Gravitational Baryogenesis

TL;DR

This paper explores how higher order Gauss-Bonnet terms coupled to baryonic currents can generate baryon asymmetry during radiation domination, extending previous Ricci scalar-based models and analyzing observational constraints.

Contribution

It introduces a novel gravitational baryogenesis mechanism using Gauss-Bonnet terms and evaluates its viability against observational data.

Findings

Gauss-Bonnet terms can produce non-zero baryon asymmetry during radiation era

Constraints on $R+F(\

gravity models are derived from baryon-to-entropy ratio calculations

Abstract

In this letter we study some variant forms of gravitational baryogenesis by using higher order terms containing the partial derivative of the Gauss-Bonnet scalar coupled to the baryonic current. This scenario extends the well known theory that uses a similar coupling between the Ricci scalar and the baryonic current. One appealing feature of the scenario we study is that the predicted baryon asymmetry during a radiation domination era is non-zero. We calculate the baryon to entropy ratio for the Gauss-Bonnet term and by using the observational constraints we investigate which are the allowed forms of the $R+F(\mathcal{G})$ gravity controlling the evolution. Also we briefly discuss some alternative higher order terms that can generate a non-zero baryon asymmetry, even in the conformal invariance limit.