Micro Black Hole Dark Matter

TL;DR

This paper explores how extra dimensions and additional species influence micro black hole radiation, potentially allowing lighter primordial black holes to serve as dark matter candidates due to suppressed evaporation effects.

Contribution

It demonstrates that low gravity scale scenarios significantly alter black hole evaporation, impacting dark matter constraints and enabling lighter primordial black holes as dark matter.

Findings

Suppression of black hole evaporation is stronger and occurs earlier.

Constraints on primordial black hole dark matter weaken substantially.

Light black holes as light as 10^{-5} M_P could be viable dark matter candidates.

Abstract

The influence of a possible low gravity scale, concretely through the presence of extra dimensions or additional species, on radiation properties of micro black holes is investigated. In particular, the suppression of evaporation through the so-called memory-burden effect is shown to be stronger, occurs earlier and with sharper transition compared to the canonical Planck-scale regime. It is furthermore shown how this affects the possibility of light primordial black hole dark matter, constraints on which may weaken substantially and allow them to be as light as $10^{-5}\,M_{\rm P}$, thereby lying in the particle regime.