Constraints on Sub-GeV Dark Matter-Electron Scattering from the CDEX-10 Experiment

Abstract

We present improved germanium-based constraints on sub-GeV dark matter via dark matter-electron (?-e) scattering using the 205.4 kg·day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted ?-e scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for m? larger than 80 MeV/c2 compared to previous germanium-based ?-e results. We also present the most stringent ?-e cross-section limit to date among experiments using solid-state detectors for m? larger than 90 MeV/c2 with heavy mediators and m? larger than 100 MeV/c2 with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new ?-e detection method with high-purity germanium detectors in ultralow radioactive background. © 2022 authors. Published by the American Physical Society.