Results of direct dark matter detection with CDEX experiment at CJPL

Abstract

Abstract The China Dark Matter Experiment (CDEX), located at the China Jinping Underground Laboratory (CJPL) whose overburden is about 2400 m rock, aims at direct searches of light Weakly Interacting Massive Particles (WIMPs). A single-element 994-gram p-type point contact (PPC) germanium detector (CDEX-1B) runs inside a solid passive shielding system. To achieve lower background, a prototype 10 kg PPC germanium detector array (CDEX-10), consisting of three detector strings with three germanium crystals each, is directly immersed in the liquid nitrogen. With the energy threshold of 160 eV, the limits on WIMP-nucleus scattering are set by energy spectra and annual modulation analysis, respectively. Incorporating Migdal effect, the data of CDEX-1B are re-analyzed to search sub-GeV WIMPs. Finally, the future plan of CDEX experiment in CJPL-II is introduced.