New cosmological constraints on primordial black holes

TL;DR

This paper updates and refines constraints on primordial black holes across a broad mass range by incorporating new effects of quark and gluon emissions, and compares various observational limits.

Contribution

It introduces the first comprehensive inclusion of quark and gluon emission effects on PBH constraints and updates observational bounds over a wide mass spectrum.

Findings

Constraints are strongest from nucleosynthesis and photon background effects.

Other constraints are weaker except in the 10^13--10^14 g range where CMB anisotropies dominate.

Updated limits on non-evaporating PBHs across 1--10^50 g.

Abstract

We update the constraints on the fraction of the Universe going into primordial black holes in the mass range 10^9--10^17 g associated with the effects of their evaporations on big bang nucleosynthesis and the extragalactic photon background. We include for the first time all the effects of quark and gluon emission by black holes on these constraints and account for the latest observational developments. We then discuss the other constraints in this mass range and show that these are weaker than the nucleosynthesis and photon background limits, apart from a small range 10^13--10^14 g, where the damping of cosmic microwave background anisotropies dominates. Finally we review the gravitational and astrophysical effects of nonevaporating primordial black holes, updating constraints over the broader mass range 1--10^50 g.