Can we identify primordial black holes? The role of subsolar gravitational wave events

TL;DR

This paper investigates whether gravitational wave signals from subsolar mass mergers can distinguish primordial black holes from stellar binaries, focusing on tidal effects and detector capabilities.

Contribution

It critically analyzes the potential to identify primordial black holes through subsolar gravitational wave events, emphasizing the role of tidal effects and detector sensitivity.

Findings

Tidal effects are significantly stronger in stellar binaries than in primordial black holes.

Current and future GW detectors can constrain tidal effects in subsolar binaries.

Detection of a subsolar merger could have profound implications for cosmology and nuclear physics.

Abstract

The detection of a subsolar object in a compact binary merger is regarded as one of the most compelling signatures of a population of primordial black holes (PBHs). We critically examine whether such systems can be distinguished from stellar binaries, such as those composed of neutron stars (NSs), which could also populate the subsolar mass range. Unlike PBHs, the gravitational-wave signal from stellar binaries is affected by tidal effects, which increase by several orders of magnitude as the mass decreases. We forecast the capability of current and future gravitational-wave (GW) detectors to constrain tidal effects in putative subsolar binaries. We also discuss the broader implications that the detection of a subsolar merger would have for both cosmology and nuclear physics.