The Magnetic Origin of Primordial Black Holes: A Viable Dark Matter Scenario

TL;DR

This paper introduces a new mechanism for primordial black hole formation linked to magnetogenesis, which can explain dark matter abundance and predicts detectable gravitational wave signals within upcoming observatory sensitivities.

Contribution

It proposes a novel PBH formation scenario within a magnetogenesis framework that accounts for observed magnetic fields and predicts observable gravitational waves.

Findings

PBHs can constitute all dark matter within a specific reheating temperature range.

The model predicts a stochastic gravitational wave background detectable by future space-based interferometers.

The scenario links primordial magnetogenesis with dark matter and gravitational wave observations.

Abstract

Primordial Black Holes (PBHs) are compelling candidates for explaining the present-day relic abundance of cold dark matter (CDM), yet their formation typically requires finely tuned early-universe dynamics. In this work, we propose a novel PBH formation mechanism within a well-established magnetogenesis framework. This scenario simultaneously accounts for the large-scale magnetic fields observed today and generates an enhanced curvature power spectrum at intermediate scales, leading to PBH formation with masses that can survive until the present epoch. We identify a narrow reheating temperature range, $10^5\,\mathrm{GeV} \leq T_{re} \leq 3\times 10^5\,\mathrm{GeV}$, within which the resulting PBHs can constitute the entirety of the observed CDM abundance. Furthermore, our model predicts a stochastic gravitational wave (GW) background as a byproduct of the PBH formation process. Remarkably, the predicted GW signal lies within the sensitivity reach of upcoming space-based interferometers, such as the LISA, DECIGO, or SKA mission, offering a direct observational probe of this PBH generation mechanism.