Probing primordial black holes with anisotropies in stochastic gravitational-wave background

Primordial black holes, if considered to constitute a significant fraction of cold dark matter, trace the inhomogeneous large-scale structure Universe. Consequently, stochastic gravitational-wave background, originating from incoherent superposition unresolved signals emitted by primordial hole binaries, is expected display anisotropies across sky. In this work, we investigate angular correlations such for first time and demonstrate their difference analogous signal produced astrophysical binaries. We carefully evaluate associated uncertainties due shot-noise cosmic variance, that studied in low-frequency regime can be differentiated origin. Our results are particularly promising stellar mass-range, where identification merger origin has been challenging.