Cosmic Coincidences of Primordial-Black-Hole Dark Matter
Résumé
If primordial black holes (PBHs) contribute more than 10% of the dark matter (DM) density, their energy density today is of the same order as that of the baryons. Such a cosmic coincidence might hint at a mutual origin for the formation scenario of PBHs and the baryon asymmetry of the Universe. Baryogenesis can be triggered by a sharp transition of the rolling rate of inflaton from slow-roll to (nearly) ultraslow-roll phases that produce large curvature perturbations for PBH formation in single-field inflationary models. We show that the baryogenesis requirement drives the PBH contribution to DM, along with the inferred PBH mass range, the resulting stochastic gravitational wave background frequency window, and the associated cosmic microwave background tensor-to-scalar ratio amplitude, into potentially observable regimes.
Mots clés
inflation: model
baryon: asymmetry
gravitational radiation: background
energy: density
gravitational radiation: stochastic
curvature: perturbation
black hole: primordial
dark matter: density
cosmic coincidence
baryogenesis
formation
inflaton
inflation: slow-roll approximation
cosmic background radiation