4,941 research outputs found

    Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jin-Ping Laboratory

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    We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (mχm_{\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⋅\cdotday exposure and 160 eVee threshold for TI analysis, and 1107.5 kg⋅\cdotday exposure and 250 eVee threshold for AM analysis. The sensitive windows in mχm_{\chi} are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σχNSI\sigma_{\chi N}^{\rm SI} at 90\% confidence level are derived as 2×2\times10−32∼7×^{-32}\sim7\times10−35^{-35} cm2\rm cm^2 for TI analysis at mχ∼m_{\chi}\sim 50−-180 MeV/c2c^2, and 3×3\times10−32∼9×^{-32}\sim9\times10−38^{-38} cm2\rm cm^2 for AM analysis at mχ∼m_{\chi}\sim75 MeV/c2−c^2-3.0 GeV/c2c^2.Comment: 5 pages, 4 figure

    Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

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    We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass pp-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 (χ{\chi}-NN) spin-independent cross sections as function of WIMP mass (mχm_{\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 mχm_{\chi}<<6 GeV/c2~{\rm GeV}/c^2 among WIMP AM measurements to date.Comment: 5 pages, 4 figure

    Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg ×{\times} day Data of the CDEX-10 Experiment

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    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 ×10−42\times 10^{-42} and 3 ×10−36\times 10^{-36} cm2^{2} at a 90\% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (mχm_{\chi}) of 5 GeV/c2{c}^2 are achieved. The lower reach of mχm_{\chi} is extended to 2 GeV/c2{c}^2.Comment: 5 pages, 4 figure

    Prevotella copri and microbiota members mediate the beneficial effects of a therapeutic food for malnutrition

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    Microbiota-directed complementary food (MDCF) formulations have been designed to repair the gut communities of malnourished children. A randomized controlled trial demonstrated that one formulation, MDCF-2, improved weight gain in malnourished Bangladeshi children compared to a more calorically dense standard nutritional intervention. Metagenome-assembled genomes from study participants revealed a correlation between ponderal growth and expression of MDCF-2 glycan utilization pathways by Prevotella copri strains. To test this correlation, here we use gnotobiotic mice colonized with defined consortia of age- and ponderal growth-associated gut bacterial strains, with or without P. copri isolates closely matching the metagenome-assembled genomes. Combining gut metagenomics and metatranscriptomics with host single-nucleus RNA sequencing and gut metabolomic analyses, we identify a key role of P. copri in metabolizing MDCF-2 glycans and uncover its interactions with other microbes including Bifidobacterium infantis. P. copri-containing consortia mediated weight gain and modulated energy metabolism within intestinal epithelial cells. Our results reveal structure-function relationships between MDCF-2 and members of the gut microbiota of malnourished children with potential implications for future therapies
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