发表机构
INFN Sezione di Firenze; Galileo Galilei Institute for Theoretical Physics（意大利国家核物理研究所佛罗伦萨分部; 伽利略·伽利莱理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究将LUX-ZEPLIN的单个高能核反冲事件解释为暗物质信号，通过精确两体运动学分析，发现吸热WIMP模型和放热模型等可行参数空间，并指出弹性散射需动量抑制或自旋依赖相互作用。
AI 中文摘要
LUX-ZEPLIN实验最近揭示了一个与反冲能量$E_R\simeq248\\,\mathrm{keV}$相容的单个核反冲事件，该事件出现在预期背景较小的区域。将此解释为暗物质的信号，我们计算了暗物质与氙核散射参数的贝叶斯后验概率分布。我们保留了入射和出射暗区态之间任意质量劈裂的精确两体运动学，从而涵盖了弹性散射和非弹性散射。数据选择了该分布中非平凡、不连通的区域，这些区域对应于物理上不同的吸热和放热机制，其中观测到的反冲要么在运动学阈值附近产生，要么通过释放暗区质量能量产生。我们确定了观测数据所偏好的反冲谱，并展示了在较低反冲能量处伴随事件的缺失如何严格约束可行的参数空间。我们发现了一个在高质量下具有通用耦合的吸热类WIMP模型的运动学调谐区域，以及从亚GeV到重暗物质且具有可观质量劈裂的放热模型。弹性暗物质散射则需要动量抑制和/或核自旋依赖的非相对论相互作用。
英文摘要
LUX-ZEPLIN has recently revealed a single nuclear recoil event compatible with a recoil energy of $E_R\simeq248\,\mathrm{keV}$, in a region with a small expected background. Interpreting this as a signature of dark matter, we compute the posterior probability distribution of the parameters of the dark matter scattering off xenon nuclei. We retain the exact two-body kinematics for an arbitrary mass splitting between the incoming and outgoing dark-sector states, thus encompassing both elastic and inelastic scatterings. The data select non-trivial, disconnected regions of this distribution, which correspond to physically distinct endothermic and exothermic regimes, in which the observed recoil is generated either close to a kinematic threshold or through the release of dark-sector mass energy. We determine the recoil spectra preferred by the observed data and show how the absence of accompanying events at lower recoil energies sharply constrains the viable parameter space. We find a kinematically tuned region of endothermic WIMP-like models at high mass for generic couplings, as well as exothermic models ranging from sub-GeV to heavy dark matter with sizable mass splittings. Elastic dark matter scatterings require instead momentum-suppressed and/or nuclear-spin-dependent non-relativistic interactions.
Comments19 pages, 7 figures, 2 tables. Added in v2: prior-robustness tests (+1 figure); preliminary analysis of the high-energy sideband & impact of boosted DM velocity component (+1 figure). Conclusions extended. Several typos fixed. References added
