Baryogenesis and Primordial Black Hole Dark Matter from Heavy Metastable Particles

TL;DR

This paper presents a scenario where a heavy metastable particle causes an early matter-dominated era, leading to primordial black hole formation that accounts for dark matter and, through decay processes, generates baryon asymmetry, all within a minimal supersymmetric framework.

Contribution

It introduces a novel mechanism linking early matter domination, primordial black holes, and baryogenesis without requiring stable dark matter particles.

Findings

Primordial black holes can constitute dark matter in this scenario.

Heavy metastable particles can generate baryon asymmetry upon decay.

The model fits within the MSSM without stable dark matter candidates.

Abstract

We propose a novel and simple scenario to explain baryon asymmetry and dark matter (DM) by utilizing an early matter-dominated era (EMDE) caused by a heavy metastable particle. Within the EMDE, lack of pressure enhances the formation of primordial black holes (PBHs) which can then contribute to the relic abundance of DM. The eventual decay of heavy metastable particle that has baryon number and $CP$ violating interactions reheats the Universe and gives rise to baryon asymmetry. Since in this setup, PBH serves as a DM candidate, the particle physics model may not require new stable degrees of freedom which leads to more freedom in the model-building side. As an example, we show that a modulus field which dominates the energy density of the Universe prior to its decay, may explain both DM and baryon asymmetry in the Universe in the context of the Minimal Supersymmetric Standard Model (MSSM) while the lightest superparticle is not stable and cannot be a DM candidate due to the R-parity violating interactions needed for baryogenesis.