Theoretical uncertainties for primordial black holes from cosmological phase transitions

TL;DR

This paper improves the theoretical prediction of primordial black hole formation from cosmological phase transitions by using precise thermodynamic calculations within realistic models, revealing limited viable parameter space for PBHs as dark matter.

Contribution

It introduces a high-precision thermodynamic analysis of PBH formation in classically conformal models, incorporating detailed nucleation dynamics and fluctuation determinants.

Findings

PBH abundance estimates are sensitive to thermodynamic details.

Viable PBH dark matter parameter space is highly constrained.

Accurate modeling narrows down conditions for PBH formation.

Abstract

Strongly supercooled first-order phase transitions have been proposed as a primordial black hole (PBH) production mechanism. While previous works rely on simplified models with limited thermodynamic precision, we stress that reliable theoretical PBH predictions require precise nucleation dynamics within realistic, classically conformal extensions of the Standard Model. By employing high-temperature dimensional reduction and computing the one-loop fluctuation determinants, we provide a state-of-the-art thermodynamic analysis and estimate the corresponding PBH abundance for classically conformal gauge-Higgs theories. Accounting for constraints from successful percolation and QCD chiral symmetry breaking, the parameter space where PBHs are viable dark matter candidates is severely limited.