Dark Matter in the Time of Primordial Black Holes

TL;DR

This paper investigates how primordial black holes and other early universe dark matter production mechanisms interact, especially during a PBH-dominated era, using a singlet scalar DM model as a case study.

Contribution

It analyzes the combined effects of Hawking evaporation and other DM production mechanisms during a PBH-dominated epoch in the early universe.

Findings

Hawking evaporation can account for the entire dark matter relic density.

The interplay between evaporation and freeze-out/freeze-in mechanisms affects DM abundance.

Nonstandard cosmological eras influence dark matter production processes.

Abstract

Hawking evaporation of primordial black holes (PBH) with masses ranging from $\sim 10^{-1}$ to $\sim 10^9$ g can generate the whole observed dark matter (DM) relic density. However, a second DM production mechanism, like freeze-out or freeze-in, could have also been active in the early universe. Here we study the interplay of these mechanisms, focusing on the scenario where PBHs dominate the energy density of the universe, leading to a nonstandard cosmological era. For concreteness, we use the singlet scalar DM model as an example for this analysis.