Zhi Zeng

We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (${m}_{\ensuremath{\chi}}$) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg day exposure and 250 eVee threshold for AM analysis. The sensitive windows in ${m}_{\ensuremath{\chi}}$ are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on ${\ensuremath{\sigma}}_{\ensuremath{\chi}N}^{\mathrm{SI}}$ at 90% confidence level are derived as $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}32}\ensuremath{\sim}7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}35}\text{ }\text{ }{\mathrm{cm}}^{2}$ for TI analysis at ${m}_{\ensuremath{\chi}}\ensuremath{\sim}50--180\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, and $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}32}\ensuremath{\sim}9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}38}\text{ }\text{ }{\mathrm{cm}}^{2}$ for AM analysis at ${m}_{\ensuremath{\chi}}\ensuremath{\sim}75\text{ }\text{ }\mathrm{MeV}/{c}^{2}--3.0\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of $8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}42}$ and $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}36}\text{ }\text{ }{\mathrm{cm}}^{2}$ at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (${m}_{\ensuremath{\chi}}$) of $5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ are achieved. The lower reach of ${m}_{\ensuremath{\chi}}$ is extended to $2\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

The China Jinping Underground Laboratory, inaugurated in 2010, is an underground research facility with the deepest rock overburden and largest space by volume in the world. The first-generation science programs include dark matter searches conducted by the CDEX and PandaX experiments. These activities are complemented by measurements of ambient radioactivity and the installation of low-background counting systems. Phase II of the facility is being constructed, and its potential research projects are being formulated. In this review, we discuss the history, key features, results, and status of this facility and its experimental programs, as well as their future evolution and plans.

We report results of a search for light dark matter weakly interacting massive particles (WIMPs) with CDEX-1 experiment at the China Jinping Underground Laboratory, based on 53.9 kg-days of data from a $p$-type point-contact germanium detector enclosed by a NaI(Tl) crystal scintillator as anti-Compton detector. The event rate and spectrum above the analysis threshold of 475 eVee are consistent with the understood background model. Part of the allowed regions for WIMP-nucleus coherent elastic scattering at WIMP mass of 6--20 GeV are probed and excluded. Independent of interaction channels, this result contradicts the interpretation that the anomalous excesses of the CoGeNT experiment are induced by dark matter, since identical detector techniques are used in both experiments.

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 ${\ensuremath{\sigma}}_{\ensuremath{\chi}N}=1.75\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}40}\text{ }\text{ }{\mathrm{cm}}^{2}$ 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.