Strong clustering of primordial black holes from Affleck-Dine mechanism

TL;DR

This paper studies how primordial black holes formed via Affleck-Dine baryogenesis tend to cluster strongly, affecting their merger rates and isocurvature perturbations, which has implications for gravitational wave observations.

Contribution

It demonstrates that PBHs formed through the AD mechanism exhibit significant clustering, altering predicted merger rates and cosmological perturbations.

Findings

PBHs show strong clustering due to AD field dynamics

Clustering significantly impacts merger rate estimates

Clustering affects isocurvature perturbation predictions

Abstract

Primordial black hole (PBH) is a fascinating candidate for the origin of binary merger events observed by LIGO-Virgo collaboration. The spatial distribution of PBHs at formation is an important feature to estimate the merger rate. We investigate the clustering of PBHs formed by Affleck-Dine (AD) baryogenesis, where dense baryon bubbles collapse to form PBHs. We found that formed PBHs show a strong clustering due to the stochastic dynamics of the AD field. Including the clustering, we evaluate the merger rate and isocurvature perturbations of PBHs, which show significant deviations from those without clustering.