Dark Matter Search with sub-keV Germanium Detectors at the China Jinping Underground Laboratory

Germanium detectors with sub-keV sensitivities open a window to search for low-mass WIMP dark matter. The CDEX-TEXONO Collaboration is conducting the first research program at the new China Jinping Underground Laboratory with this approach. The status and plans of the laboratory and the experiment are discussed. The theme of the CDEX-TEXONO research program is on the studies of low energy neutrino and dark matter physics. The current objectives are to open the “sub-keV ” detector window with germanium detectors [1]. The generic “benchmark ” goals in terms of detector performance are: (1) modular target mass of order of 1 kg; (2) detector sensitivities reaching the range of 100 eV; (3) background at the range of 1 kg−1keV−1day−1 (cpkkd). The neutrino physics program [2] is pursued at the established Kuo-Sheng Reactor Neutrino Laboratory (KSNL), while dark matter searches will be conducted at the new China Jin-Ping Underground Laboratory (CJPL) [3] officially inaugurated in December 2010. The three main scientific subjects are neutrino magnetic moments, neutrino-nucleus coherent scattering, and dark matter searches. We highlight the status and plans of the dark matter program in this article. There are compelling evidence that about one-quarter of the energy density in the univers