Torsion-balance search for ultralow-mass bosonic dark matter

We used a stationary torsion balance with a beryllium-aluminum composition dipole to search for ultralow-mass bosonic dark matter coupled to baryon minus lepton number. We set 95% confidence limits on the coupling constant g_B-L for bosons with masses between 10^-18 and 10^-16 eV/c² with the best performance at mDM=8×10^-18 eV/c² constraining g_B-L(c)^-1/2<1×10^-25. This provides a complimentary limit to equivalence-principle experiments that search for ultralow-mass bosons as force-mediating particles.