Distinguishing between dark-matter interactions with gravitational-wave detectors

Ground-based gravitational-wave interferometers could directly probe the existence of ultralight dark matter [O(10-14-10-11) eV/c2] that couples to standard model particles in the detectors. Recently, many techniques have been developed to extract a variety of potential dark-matter signals from noisy gravitational-wave data; however, little effort has gone into ways to distinguish between types of dark matter that could directly interact with the interferometers. In this work, we employ the Wiener filter to follow-up candidate dark-matter interaction signals. The filter captures the stochastic nature of these signals and, in simulations, successfully identifies which type of dark matter interacts with the interferometers. The power of this method to distinguish between different types of dark matter comes from different coupling mechanisms that result in different power spectra, as well as different correlations between detectors spread across the Earth. We apply the Wiener filter to outliers that remained in the LIGO/Virgo/KAGRA search for dark photons in data from the most recent observing (O3) [R. Abbott (LIGO Scientific, Virgo, KAGRA Collaborations), Phys. Rev. D 105, 063030 (2022)PRVDAQ2470-001010.1103/PhysRevD.105.063030] and show that they are consistent with noise disturbances. Our proof-of-concept analysis demonstrates that the Wiener filter can be a powerful technique to confirm or deny the presence of dark-matter interaction signals in gravitational-wave data and distinguish between scalar and vector dark-matter interactions.