A torsion-balance search for ultra low-mass bosonic dark matter

TL;DR

This study used a torsion balance to set new limits on ultra low-mass bosonic dark matter coupling to baryon minus lepton number, improving constraints in a previously unexplored mass range.

Contribution

It provides the first direct experimental constraints on ultra low-mass bosonic dark matter coupling in the mass range of 10^{-18} to 10^{-16} eV/c^2 using a torsion-balance method.

Findings

Set 95% confidence limits on $g_{B-L}$ coupling constant.

Achieved best constraint at $m_{DM} = 8×10^{-18}$ eV/$c^2$.

Provided complementary limits to equivalence-principle experiments.

Abstract

We used a stationary torsion balance with a beryllium-aluminum composition dipole to search for ultra low-mass bosonic dark matter coupled to baryon minus lepton number. We set 95% confidence limits on the coupling constant $g_{\rm B-L}$ for bosons with masses between $10^{-18}$ and $10^{-16}$ eV/$c^2$ with the best performance at $m_{\rm DM} = 8\times 10^{-18}$ eV/$c^2$ constraining $g_{B-L}(\hbar c)^{-1/2} < 1 \times 10^{-25}$. This provides a complimentary limit to equivalence-principle experiments that search for ultra low-mass bosons as force-mediating particles.