The impact of particle production on gravitational baryogenesis

J.A.S Lima,D Singleton

doi:10.1016/j.physletb.2016.10.005

Abstract

Baryogenesis driven by curvature effects is investigated by taking into account gravitationally induced particle production in the very early Universe. In our scenario, the baryon asymmetry is generated dynamically during an inflationary epoch powered by ultra-relativistic particles. The adiabatic particle production rate provides both the needed negative pressure to accelerate the radiation dominated Universe and a non-zero chemical potential which distinguishes baryons and anti-baryons thereby producing a baryon asymmetry in agreement with the observed value. Reciprocally, the present day asymmetry may be used to determine the inflationary scale at early times. Successful gravitational baryogenesis is dynamically generated for many different choices of the relevant model parameters.

Highlights

A well known but still challenging cosmological fact is that the number of baryons in the visible Universe is much larger than the number of anti-baryons
The agreement between Big-bang nucleosynthesis predictions and the cosmic background radiation (CMB) observations suggests that the above ratio has remained constant at least since the cosmic factory started the production of the light elements
In this paper we have investigated the early generation of Basymmetry driven by curvature effects, in the context of gravitationally induced particle production models

Summary

Introduction

A well known but still challenging cosmological fact is that the number of baryons in the visible Universe is much larger than the number of anti-baryons. Different from many variants of inflation, there is no Big-bang singularity (or horizon problem), and the exact, but unstable, primordial de Sitter stage evolves smoothly to the standard radiation FRW phase when the particle production ends – in agreement with conformal invariance [37]. In this context, we show that the observed B-asymmetry is naturally generated during a warm inflationary period with ω.

Inflation induced by gravitational particle production

Particle production and curvature baryogenesis

Findings

Summary and conclusions