First search for light fermionic dark matter absorption on electrons using germanium detector in CDEX-10 experiment

Abstract

We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4~kg$\cdot$day data collected by the CDEX-10 experiment, with the analysis threshold of 160~eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM--electron interaction. We present new constraints of cross section in the DM range of 0.1--10 keV/$c^2$ for vector and axial-vector interaction. The upper limit on the cross section is set to be $6.8\times 10^{-46}\mathrm{c}{\mathrm{m}}^2$ for vector interaction, and $2.3\times 10^{-46}\mathrm{c}{\mathrm{m}}^2$ for axial-vector interaction at DM mass of 5 keV/$c^2$.

Comments: 6 pages, 4 figures. Version updated to match PRD version