Quasi-evaporating black holes and cold dark matter

TL;DR

This paper explores the possibility that primordial black holes, which lose only a small fraction of their mass, could serve as viable cold dark matter candidates without conflicting with nucleosynthesis or cosmic background constraints.

Contribution

It investigates the implications of Vilkovisky's black hole backreaction scenario for primordial black holes as dark matter, focusing on their mass spectrum and observational constraints.

Findings

Primordial black holes around 10 grams could constitute dark matter.

Such black holes are not ruled out by nucleosynthesis constraints.

They evade limits from cosmic radiation background contributions.

Abstract

Vilkovisky has claimed to have solved the black hole backreaction problem and finds that black holes lose only ten percent of their mass to Hawking radiation before evaporation ceases. We examine the implications of this scenario for cold dark matter, assuming that primordial black holes are created during the reheating period after inflation. The mass spectrum is expected to be dominated by 10-gram black holes. Nucleosynthesis constraints and the requirement that the earth presently exist do not come close to ruling out such black holes as dark matter candidates. They also evade the demand that the photon density produced by evaporating primordial black holes does not exceed the present cosmic radiation background by a factor of about one thousand.