Dark Matter Constraints from Isomeric ${}^{\mathbf{178}\mathbf{m}}$Hf

We describe a first measurement of the radiation from a ${}^{\mathbf{178}\mathbf{m}}$Hf sample to search for dark matter. The $\gamma$ flux from this sample, possessed by Los Alamos National Laboratory nuclear chemistry, was measured with a Ge detector at a distance of 4 ft due to its high activity. We search for $\gamma$s that cannot arise from the radioactive decay of ${}^{\mathbf{178}\mathbf{m}}$Hf, but might arise from the production of a nuclear state due to the inelastic scattering with dark matter. The limits obtained on this $\gamma$ flux are then translated into constraints on the parameter space of inelastic dark matter. Finally, we describe the potential reach of future studies with ${}^{\mathbf{178}\mathbf{m}}$Hf.