W. Zhao, Q. Yue, K. J. Kang et al.
First results on low-mass WIMPs from the CDEX-1 experiment at the China Jinping underground laboratory
Phys. Rev. D 88, 052004 (2013)
The China Dark Matter Experiment Collaboration reports the first experimental limit on weakly interacting massive particles (WIMPs) dark matter from 14.6 kg-days of data taken with a 994 g p-type point-contact germanium detector at the China Jinping underground laboratory where the rock overburden is more than 2400 m. The energy threshold achieved was 400 eVee. According to the 14.6 kg-day live data, we placed the limit of σxN =1.75×10-40m2 at a 90% confidence level on the spin-independent cross section at a WIMP mass of 7 GeV before differentiating bulk signals from the surface backgrounds.