Constraints on Primordial Black Hole Dark Matter from the Stochastic Gravitational-Wave Background

Abstract

This work investigates the contribution of primordial black hole (PBH) binaries to the stochastic gravitational-wave background (SGWB) using data from the LIGO--Virgo--KAGRA (LVK) collaboration. A Bayesian inference framework is employed to model the PBH population with a log-normal mass distribution, incorporating early binary formation and suppression effects from environmental interactions such as tidal disruptions and clustering. Observational limits from the LVK O1-O3 runs are used to constrain the PBH dark matter fraction. The results place stringent upper bounds on PBH abundances in the 0.05-10 M⊙ mass range and demonstrate that suppression effects significantly reduce the allowed parameter space. These refined constraints are essential for assessing the role of PBHs as dark matter candidates and emphasize the importance of future observations with instruments such as LIGO O4, LISA, and DECIGO.