Probing Primordial Black Hole Scenarios with Terrestrial Gravitational Wave Detectors

Abstract

It is possible that primordial black holes consitute (or consituted) a significant fraction of the energy budget of our universe. Terrestrial gravitational wave detectors offer the opportunity to test the existence of primordial black holes in two different mass ranges, from $10^2\,{\rm g}-10^{16}\,{\rm g}$ to $10^{-6}\,M_\odot-100 \,M_\odot$. The first mass window is open via induced gravitational waves and the second one by gravitational waves from binary mergers. In this review, we outline and explain the different gravitational wave signatures of primordial black holes that may be probed by terrestrial gravitational wave detectors, such as the current LIGO/Virgo/KAGRA and future ones like Einstein Telescope and Cosmic Explorer. We provide rough estimates for the frequency and amplitude of the associated GW background signals. We also discuss complementary probes for these primordial black hole mass ranges.