Composite Asymmetric Dark Matter from Primordial Black Holes

TL;DR

This paper proposes a novel cosmological model where primordial black holes evaporate to produce asymmetries in baryons and dark matter, explaining their observed densities through a composite asymmetric dark matter framework with a dark QCD-like sector.

Contribution

It introduces a cogenesis scenario linking primordial black hole evaporation to asymmetric dark matter and baryogenesis within a composite dark sector, with specific mass ranges for particles and black holes.

Findings

Explains observed baryon and dark matter densities.

Identifies mass ranges for scalar particles and black holes.

Ensures consistency with cosmological constraints.

Abstract

We investigate a cogenesis scenario for composite asymmetric dark matter framework: a dark sector has a similar strong dynamics to quantum chromodynamics in the standard model, and the dark-sector counterpart of baryons is the dark matter candidate. The Hawking evaporation of primordial black holes plays the role of a source of heavy scalar particles whose $CP$-violating decay into quarks and dark quarks provides particle--anti-particle asymmetries in baryons and dark matter, respectively. Primordial black holes should evaporate after the electroweak phase transition and before the big-bang nucleosynthesis for explaining the baryon asymmetry of the Universe and for consistent cosmology. We find that this scenario explains the observed values for both baryon and dark matter energy densities when the heavy scalar particles have a mass of $10^6 \text{--} 10^9\, \mathrm{GeV}$ and the primordial black holes have masses of $10^7 \text{--} 10^9\,\mathrm{g}$.