A Search for Ultra-Light Vector Dark Matter with a Rotating Torsion Balance

We search for ultra-light vector dark matter interacting with a rotating torsion balance with a baryon minus lepton number composition dipole. Our search spans candidate masses in the ultra-low mass range from 1.3~$\times10^{-22}$ to 1.9~$\times10^{-18}$ eV. We set limits on the coupling strength to baryon minus lepton number for each dark matter candidate reaching a peak sensitivity of $g_{B-L} \leq 9 \times 10^{-26}$.