Search for small-mass black-hole dark matter with space-based gravitational wave detectors

Abstract

If the halo dark matter were composed of primordial black holes (PBHs) with mass between 10^16 and 10^20 g, their gravitational interaction with test masses of laser interferometer may lead to a detectable pulselike signal during the fly-by. If a proof-mass noise of 3×10-15 m/s^2/Hz^1/2 down to ~10^-5 Hz is achieved by the Laser Interferometer Space Antenna, the event rate, with signal-to-noise ratios greater than 5, could become ~0.1 per decade, involving black holes of mass ~10^17 g. The detection rate could improve significantly for future space-based interferometers, though these events must be distinguished from those involving perturbations due to near-Earth asteroids. While the presence of primordial black holes below a mass of ~10^16 g is now constrained based on the radiation released during their evaporation, the gravitational-wave detectors could potentially extend the search for PBHs to several orders of magnitude higher masses.