Accreting Primordial Black Holes as Dark Matter Constituents

TL;DR

This paper proposes that primordial black holes accreting positronium plasma via magnetic processes could account for a significant portion of dark matter, challenging previous accretion models.

Contribution

It introduces a novel magnetic accretion mechanism for primordial black holes as a dark matter candidate, contrasting with traditional Bondi accretion models.

Findings

Magnetic accretion can explain dark matter abundance.

Bondi accretion is ruled out by gamma radiation constraints.

Various accretion scenarios are analyzed.

Abstract

We show how magnetic accretion of positronium (electron-positron) plasma by primordial black holes might significantly contribute to the mass of dark matter in the present Universe. Assuming that background gamma radiation is primordial black hole Hawking radiation rules out Bondi accretion, while magnetic accretion known from studies of active galactic nuclei could explain the abundance of dark matter. Various accretion scenarios are discussed.