Collider Constraints on a Dark Matter Interpretation of the XENON1T Excess

Abstract

In light of the excess in the low-energy electron recoil events reported by XENON1T, many new physics scenarios have been proposed as a possible origin of the excess. One possible explanation is that the excess is a result of a fast moving dark matter (DM), with velocity $v\sim 0.05-0.20$ and mass between 1 MeV and 10 GeV, scattering off an electron. Assuming the fast moving DM-electron interaction is mediated by a vector particle, we derive collider constraints on the said DM-electron interaction. The bounds on DM-electron coupling is then used to constrain possible production mechanisms of the fast moving DM. We find that the preferred mass of the vector mediator is relatively light ($\lesssim$ 1 GeV) and the coupling of the vector to the electron is much smaller than the coupling to the fast moving DM.

Comments: 6 pages, 5 figures, references added, CMB constraints included, low-energy bounds updated, conclusion unchanged