A New Probe of Dark Matter-Induced Fifth Force with Neutron Star Inspirals

TL;DR

This paper proposes a novel method to detect light scalar dark matter by observing its effects on neutron star binary inspirals through gravitational wave signals, especially in broadband detectors.

Contribution

It introduces a new approach to probe light scalar dark matter using gravitational wave observations of neutron star inspirals, leveraging the long coherence time and high-frequency GW cycles.

Findings

Future GW detectors can explore previously unconstrained dark matter parameter space.

The method enhances sensitivity by utilizing the large number of GW cycles during inspiral.

Long wave coherence of dark matter induces detectable oscillating mass shifts in neutron stars.

Abstract

A light scalar dark matter (DM) is allowed in a wide range of the mass and interaction types. We show that the light scalar DM may be probed in a new way from final years of neutron-star (NS) binary inspirals. If the DM interacts with the neutron, its long wave coherence in the background can induce the time-oscillating mass shift, to which the binary inspiral is inherently sensitive. But the sensitivity is found to be significantly enhanced by a large number of gravitational-wave (GW) cycles during year-long highest-frequency measurements in the broadband $f \simeq 0.01-1000$ Hz. The future broadband detector networks including LIGO-band detectors can probe unconstrained parameter space of the light scalar DM.