Ultraviolet freeze-in baryogenesis

TL;DR

This paper proposes a UV freeze-in baryogenesis mechanism where out-of-equilibrium scattering processes produce dark matter and generate matter-antimatter asymmetry via CP violation, with scenarios involving scalar and fermion dark matter at keV masses.

Contribution

It introduces a novel UV freeze-in baryogenesis model using non-renormalizable operators to explain dark matter and baryon asymmetry simultaneously.

Findings

Feasible for dark matter in the keV mass range

Produces both dark matter density and baryon asymmetry

Applicable to scalar and fermion dark matter scenarios

Abstract

We study a mechanism through which the cosmic dark matter density can be explained simultaneously with the observed baryon asymmetry of the Universe. At the core of our proposal lie the out-of-equilibrium scattering processes of bath particles which are responsible for the production of feebly-interacting dark matter. The same processes violate $CP$, which further leads to an asymmetry between matter and antimatter being generated in the visible sector. We focus on the possibility that these interactions are described through non-renormalizable operators, which leads to both dark matter and the baryon asymmetry being produced at high temperatures. The mechanism is exemplified by studying two concrete scenarios, one involving scalar and one involving fermion dark matter. We find that in both cases it is, indeed, possible to achieve a common explanation for the dark matter content and the matter-antimatter asymmetry of the Universe, provided that dark matter is in the keV mass range.