Dark Matter and Leptogenesis from Gravitational Production

TL;DR

This paper investigates the gravitational production of dark matter and right-handed neutrinos, exploring how their interactions and decay influence the early universe's entropy, baryon asymmetry, and dark matter abundance.

Contribution

It proposes a model where dark matter and leptogenesis are simultaneously generated through gravitational interactions and neutrino decays, linking these phenomena.

Findings

Constraints on reheating dynamics from entropy injection

Potential for right-handed neutrinos to generate baryon asymmetry

Relations between dark matter properties and neutrino decay parameters

Abstract

Since the gravitational interaction is universal, any particle that ever existed, if kinematically accessible, has to be produced through her. We explore the possibility that dark matter is generated purely from gravitational scatterings together with heavy Majorana right-handed neutrinos that are long-lived. Their late decay could inject significant entropy into the thermal bath, diluting both the dark matter abundance and the cosmic baryon asymmetry, thereby imposing various constraints on the reheating dynamics. Additionally to the entropy injection, long-lived right-handed neutrinos could also be responsible for generating the baryon asymmetry through leptogenesis, and hence establish some nontrivial relations between the dark matter and the right-handed properties, and the reheating dynamics