Z. Y. Zhang, L. T. Yang, Q. Yue et al.
Experimental Limits on Solar Reflected Dark Matter with a New Approach on Accelerated-Dark-Matter--Electron Analysis in Semiconductors
Phys. Rev. Lett. 132, 171001 (2024)
Recently a dark matter--electron (DM--electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM--electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM--electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM--electron interaction is presented with the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5$-$15 keV/$c^2$, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1 MeV/$c^2$ is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM--electron analyses with semiconductor detectors.