Inelastic Dark Matter Electron Scattering and the XENON1T Excess

Abstract

Detection of electron recoils by dark matter (DM) may reveal the structure of the dark sector. We consider a scenario where a heavier DM particle inelastically scatters off an electron and is converted into a lighter DM particle. A small mass difference between the two DM particles is transferred into electron recoil energy. We investigate the DM-electron interaction mediated by a massive dark photon and evaluate the inelastic DM scattering rate, taking account of the atomic structure. It is found that the scattering rate is significantly enhanced because of the small mass splitting, which allows for a small momentum transfer matched with the size of the electron wave function. We show that there exists a viable parameter space which explains the excess of electron recoil events around 2-3 keV recently reported by the XENON1T experiment.

7 pages, 5 figures, version to be published in Physics Letters B

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Cited by in corpus (8)

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• Solar Neutrino Scattering with Electron into Massive Sterile Neutrino
• The ups and downs of inelastic dark matter: Electron recoils from terrestrial upscattering
• Xenon-1T excess as a possible signal of a sub-GeV hidden sector dark matter
• Solar Active-Sterile Neutrino Conversion with Atomic Effects at Dark Matter Direct Detection Experiments
• Axion emission from nuclear magnetic dipole transitions
• Explaining The XENON1T Excess With Light Goldstini Dark Matter
• Inelastic Dark Matter at the Fermilab Short Baseline Neutrino Program