Probing For Non-Gravitational Long-Range Dark Matter Interactions

Dark matter remains a mystery in fundamental physics. The only evidence for dark matter's existence is from gravitational interactions. We constructed a precision torsion balance experiment to search for non-gravitational, long-range interactions between ordinary matter in our lab and the Milky Way's dark matter. We find no evidence of such interaction and set strict upper bounds on its strength. These results suggest that dark matter only interacts gravitationally over long distances and constrains a variety of dark matter theories.