Asteroids for ultralight dark-photon dark-matter detection

Gravitational-wave (GW) detectors that monitor fluctuations in the separation between inertial test masses (TMs) are sensitive to new forces acting on those TMs. Ultralight dark-photon dark matter (DPDM) coupled to U(1)B or U(1)B-L charges supplies one such force that oscillates with a frequency set by the DPDM mass. GW detectors operating in different frequency bands are thus sensitive to different DPDM mass ranges. A recent GW detection proposal based on monitoring the separation of certain asteroids in the inner Solar System would have sensitivity to mu Hz frequencies [M. A. Fedderke et al., Asteroids for mu Hz gravitational-wave detection, Phys. Rev. D 105, 103018 (2022)]. In this paper, we show how that proposal would also enable access to new parameter space for DPDM coupled to B [respectively, B - L] charges in the mass range 5[9] x 10-21 eV < mDM < 2 x 10-19 eV, with peak sensitivities about a factor of 500 [50] beyond current best limits on epsilon B [epsilon B-L] at mDM ' 2 x 10-19 eV. Sensitivity could be extended up to mDM ' 2 x 10-18 eV only if noise issues associated with asteroid rotational motion could be overcome.

Automated summary

Gravitational-wave detectors can detect new forces acting on test masses through the fluctuations in their separation. A recent proposal based on monitoring the separation of certain asteroids in the inner Solar System would provide sensitivity to mu Hz frequencies and allow exploration of the parameter space for dark matter. However, noise issues associated with asteroid rotational motion need to be overcome for sensitivity to be extended to higher mass ranges.