Cosmology and nuclear-physics implications of a subsolar gravitational-wave event

TL;DR

This paper discusses the potential implications of detecting a subsolar-mass gravitational-wave event, which could reveal new insights into exotic compact objects, dark matter, and neutron star composition.

Contribution

It demonstrates that the nature of a subsolar binary can be confidently inferred during the current observing run using tidal deformability effects.

Findings

Subsolar-mass gravitational wave signals can distinguish between neutron stars, primordial black holes, and exotic objects.

Detection of primordial black holes would impact cosmology and dark matter theories.

Measuring tidal deformability could confirm or refute the existence of strange quark stars.

Abstract

Detecting a compact subsolar object would have profound implications in physics, the reach of which depends on the nature of the object. Here we explore such consequences for a putative subsolar-mass gravitational wave event detected by the LIGO-Virgo-KAGRA Collaboration. We forecast that the nature of a subsolar binary (made of light neutron stars, primordial black holes, or more exotic compact objects) can be inferred with a great statistical confidence level already during the ongoing fourth observing run, based on the large tidal deformability effects on the signal. The detection of a primordial black hole would have implications for cosmology and dark matter scenarios, while the measurement of the tidal deformability of a subsolar neutron star could rule out or confirm the existence of strange stars made of quarks.