Dark matter and dark radiation from evaporating Kerr primordial black holes

TL;DR

This paper investigates how rotating (Kerr) primordial black holes contribute to dark matter and dark radiation production during evaporation, extending previous Schwarzschild black hole models and analyzing observational constraints.

Contribution

It generalizes previous dark matter and dark radiation production models from black hole evaporation to include black hole spin effects, especially for Kerr black holes.

Findings

Kerr black holes do not significantly alter dark matter bounds.

Dark radiation predictions remain similar to Schwarzschild case.

Enhanced signals for spin 2 particles require extremal black holes.

Abstract

The mechanism of the generation of dark matter and dark radiation from the evaporation of primordial black holes is very interesting. We consider the case of Kerr black holes to generalize previous results obtained in the Schwarzschild case. For dark matter, the results do not change dramatically and the bounds on warm dark matter apply similarly: in particular, the Kerr case cannot save the scenario of black hole domination for light dark matter. For dark radiation, the expectations for $\Delta N_{eff}$ do not change significantly with respect to the Schwarzschild case, but for an enhancement in the case of spin 2 particles: in the massless case, however, the projected experimental sensitivity would be reached only for extremal black holes.