S. Y. Wu

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 $2\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We present new constraints on light dark matter boosted by cosmic rays (CRDM) using the 205.4 kg day data of the CDEX-10 experiment conducted at the China Jinping Underground Laboratory. The Monte Carlo simulation package cjpl_ess was employed to evaluate the Earth shielding effect. Several key factors have been introduced and discussed in our CRDM analysis, including the contributions from heavier CR nuclei than proton and helium, the inhomogeneity of CR distribution, and the impact of the form factor in the Earth attenuation calculation. Our result excludes the dark matter--nucleon elastic scattering cross section region from $1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}$ to ${10}^{\ensuremath{-}26}\text{ }\text{ }{\mathrm{cm}}^{2}$ for dark matter of $10\text{ }\text{ }\mathrm{keV}/{c}^{2}$ to $1\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.

We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling ${g}_{Ae}<2.48\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ from Compton, bremsstrahlung, atomic-recombination, and deexcitation channels and ${g}_{AN}^{\mathrm{eff}}\ifmmode\times\else\texttimes\fi{}{g}_{Ae}<4.14\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$ from a $^{57}\mathrm{Fe}$ M1 transition at 90% confidence level.

PandaX is a large upgradable liquid-xenon detector system that can be used for both direct dark-matter detection and $^{136}$Xe double-beta decay search. It is located in the Jinping Deep-Underground Laboratory in Sichuan, China. The detector operates in dual-phase mode, allowing detection of both prompt scintillation, and ionization charge through proportional scintillation. The central time projection chamber will be staged, with the first stage accommodating a target mass of about 120\,kg. In stage II, the target mass will be increased to about 0.5\,ton. In the final stage, the detector can be upgraded to a multi-ton target mass. In this paper a detailed description of the stage-I detector design and performance results established during the commissioning phase is presented.