Gravitational production of matter and radiation during reheating

TL;DR

This paper investigates how matter and radiation are produced during the reheating phase after inflation solely through gravitational interactions, demonstrating a minimal scenario that explains dark matter, baryon asymmetry, and thermalization.

Contribution

It introduces a minimal gravitational portal model that accounts for dark matter, leptogenesis, and reheating without additional interactions.

Findings

Gravitational interactions can produce the observed dark matter relic density.

The model explains baryon asymmetry via leptogenesis.

Reheating temperature is sufficient for thermal bath formation.

Abstract

I present the production of matter and radiation during reheating after inflation, considering only gravitational interactions between the inflaton background and the other sectors. Processes considered are the following: i) the exchange of a graviton, $h_{\mu \nu}$, involved in the scattering of the inflaton or particles in the newly created radiation bath; ii) scattering of the inflaton background and particles in the radiation bath including the effects of non-minimal couplings to curvature of the Higgs boson and the inflaton. Requiring the existence of heavy right-handed neutrinos (RHN), I show that a minimal scenario utilizing only these "gravitational portals" is able to generate simultaneously the observed relic density of Dark Matter (DM), the baryon asymmetry through leptogenesis, as well as a sufficiently hot thermal bath after inflation, for generic models of large field inflation.