No Arabic abstract
We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses ($m_{chi}$) 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$cdot$day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg$cdot$day exposure and 250 eVee threshold for AM analysis. The sensitive windows in $m_{chi}$ are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on $sigma_{chi N}^{rm SI}$ at 90% confidence level are derived as $2times$10$^{-32}sim7times$10$^{-35}$ $rm cm^2$ for TI analysis at $m_{chi}sim$ 50$-$180 MeV/$c^2$, and $3times$10$^{-32}sim9times$10$^{-38}$ $rm cm^2$ for AM analysis at $m_{chi}sim$75 MeV/$c^2-$3.0 GeV/$c^2$.
We report constraints on the dark photon effective kinetic mixing parameter (${kappa}$) with data taken from two ${p}$-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90% confidence level upper limits on ${kappa}$ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (${m_V}$) from 10 to 300 eV/${c^2}$ in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90% confidence level with ${m_V}$ from 0.1 to 4.0 keV/${c^2}$ are set from 449.6 kg-day data, with a minimum of ${rm{kappa=1.3 times 10^{-15}}}$ at ${rm{m_V=200 eV/c^2}}$.
We report the results of searches for solar axions and galactic dark matter axions or axion-like particles with CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg-days of data from a p-type point-contact germanium detector. The data are compatible with the background model and no excess signals are observed. Limits of solar axions on the model independent coupling $g_{Ae}<2.5times10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and deexcitation channel and $g^{text{eff}}_{AN}times g_{Ae}<6.1times10^{-17}$ from $^{57}$Fe M1 transition at 90 % confidence level are derived. Within the framework of the DFSZ and KSVZ models, our results exclude the axion mass heavier than 0.9 eV/c$^{2}$ and 173 eV/c$^{2}$, respectively. The derived constraints for dark matter axions below 1 keV improves over the previous results.
We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass $p$-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2 yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (${chi}$-$N$) spin-independent cross sections as function of WIMP mass ($m_{chi}$) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at $>$99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at $m_{chi}$$<$6$~{rm GeV}/c^2$ among WIMP AM measurements to date.
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 $g_{Ae} < 2.48 times 10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and de-excitation channels and $g^{eff}_{AN} times g_{Ae} < 4.14 times 10^{-17}$ from a $^{57}$Fe M1 transition at 90% confidence level.
The China Dark matter Experiment collaboration reports the first experimental limit on WIMP dark matter from 14.6 kg-day 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 N= 1.75 * 10^{-40} cm^{2} at 90% confidence level on the spin-independent cross-section at WIMP mass of 7 GeV before differentiating bulk signals from the surface backgrounds.