The Dark Side of the Moon: Listening to Scalar-Induced Gravitational Waves

TL;DR

This paper explores how primordial black holes formed from early universe perturbations could produce detectable scalar-induced gravitational waves in the microhertz range, with implications for future lunar and satellite laser ranging experiments.

Contribution

It derives projected constraints on primordial black hole populations from potential non-detections of gravitational waves, considering effects like the electroweak phase transition and recent microlensing data.

Findings

Projected constraints on primordial black holes from gravitational wave non-detections.

Impact of electroweak phase transition on black hole abundance.

Connection between gravitational wave constraints and microlensing observations.

Abstract

The collapse of large-amplitude primordial curvature perturbations into planetary-mass primordial black holes generates a scalar-induced gravitational wave background in the $\mu $Hz frequency range that may be detectable by future Lunar Laser Ranging and Satellite Laser Ranging data. We derive projected constraints on the primordial black hole population from a null detection of stochastic gravitational wave background by these experiments, including the impact of the electroweak phase transition on the abundance of planetary-mass primordial black holes. We also discuss the connection between the obtained projected constraints and the recent microlensing observations by the HSC collaboration of the Andromeda Galaxy.