Primordial Black Holes as Dark Matter through Higgs Criticality

TL;DR

This paper investigates whether Higgs field fluctuations during inflation can produce enough primordial black holes to account for dark matter, concluding they cannot due to insufficient abundance and gravitational wave production.

Contribution

It demonstrates that Higgs fluctuations do not lead to viable primordial black hole dark matter, analyzing both Standard Model and modified Higgs potentials with nonlinear perturbation tracking.

Findings

Higgs fluctuations are larger on CMB scales than on PBH scales.

Superhorizon perturbations are not converted into large curvature fluctuations.

Higgs fluctuations do not produce enough PBHs or significant gravitational waves.

Abstract

We study the dynamics of a spectator Higgs field which stochastically evolves during inflation onto near-critical trajectories on the edge of a runaway instability. We show that its fluctuations do not produce primordial black holes (PBHs) in sufficient abundance to be the dark matter, nor do they produce significant second-order gravitational waves. First we show that the Higgs produces larger fluctuations on CMB scales than on PBH scales, itself a no-go for a viable PBH scenario. Then we track the superhorizon perturbations nonlinearly through reheating using the delta N formalism to show that they are not converted to large curvature fluctuations. Our conclusions hold regardless of any fine-tuning of the Higgs field for both the Standard Model Higgs and for Higgs potentials modified to prevent unbounded runaway.