Scalar fields around black hole binaries in LIGO-Virgo-KAGRA

TL;DR

This paper develops a semi-analytic gravitational waveform model to detect or constrain light scalar fields around black hole binaries using LIGO-Virgo-KAGRA data, providing new limits and tentative evidence for scalar environments.

Contribution

It introduces a novel semi-analytic waveform model validated against simulations and applies Bayesian analysis to gravitational-wave data to probe scalar fields around black holes.

Findings

Upper limits on scalar densities around most binaries.

Vacuum models outside 95% credible region for GW190728 and GW190814.

Tentative evidence for a light scalar around GW190728 with Bayes factor ~3.5.

Abstract

Light scalar particles arise naturally in many extensions of the Standard Model and are compelling dark-matter candidates. Gravitational interactions near black holes can trigger the growth of dense scalar configurations that, if sustained during inspiral, alter binary dynamics and imprint signatures on gravitational-wave signals. Detecting such effects would provide a novel probe of fundamental physics and dark matter. Here we develop a semi-analytic waveform model for binaries in scalar environments, validate it against numerical relativity simulations, and apply it in a Bayesian analysis of the LIGO-Virgo-KAGRA catalog. We obtain physically meaningful upper limits on scalar densities around most compact binaries. For GW190728 and GW190814, vacuum lies outside the $95\%$ credible region. When including superradiance priors, GW190728 shows tentative evidence for a scalar environment with a Bayes factor of $\ln \mathrm{B}^{\rm env}_{\rm vac} \approx 3.5$, consistent with a light scalar of mass $\sim10^{-12}\,\mathrm{eV}$.