Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084.
Institute of Physics, Academia Sinica, Taipei 11529.
Phys Rev Lett. 2019 Oct 18;123(16):161301. doi: 10.1103/PhysRevLett.123.161301.
We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (m_{χ}) 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_{χ} are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σ_{χN}^{SI} at 90% confidence level are derived as 2×10^{-32}∼7×10^{-35} cm^{2} for TI analysis at m_{χ}∼50-180 MeV/c^{2}, and 3×10^{-32}∼9×10^{-38} cm^{2} for AM analysis at m_{χ}∼75 MeV/c^{2}-3.0 GeV/c^{2}.
我们报告了通过包含 Migdal 效应的弱相互作用大质量粒子（WIMP）与核自旋独立散射来搜索亚GeV 质量（mχ）的结果。对 CDEX-1B 数据进行了时间积分（TI）和年度调制（AM）效应的分析，TI 分析的暴露量为 737.1 kg·天，阈值为 160 eVee，AM 分析的暴露量为 1107.5 kg·天，阈值为 250 eVee。通过包含 Migdal 效应，mχ 的敏感窗口扩展了一个数量级，以降低 DM 质量。在 mχ∼50-180 MeV/c2 处，在包含 Migdal 效应的 TI 分析中，在 90%置信水平下，σχN SI的新限制为 2×10-32∼7×10-35 cm2，在 mχ∼75 MeV/c2-3.0 GeV/c2 处，在 AM 分析中，为 3×10-32∼9×10-38 cm2。
