Dark matter repulsion could thwart direct detection

Abstract

We consider a feeble repulsive interaction between ordinary matter and dark matter, with a range similar to or larger than the size of the Earth. Dark matter can thus be repelled from the Earth, leading to null results in direct detection experiments, regardless of the strength of the short-distance interactions of dark matter with atoms. Generically, such a repulsive force would not allow trapping of dark matter inside astronomical bodies. In this scenario, accelerator-based experiments may furnish the only robust signals of asymmetric dark matter models, which typically lack indirect signals from self-annihilation. Some of the variants of our hypothesis are also briefly discussed.