GAIA 与 LZ 相遇：高速尾部是暗物质的显著信号
GAIA meets LZ: a high velocity tail-tale sign for dark matter
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中文总结 AI 辅助
本研究结合 Gaia 数据与 LZ 实验事件，发现银河系速度分布的高速尾部显著影响非弹性暗物质解释，并扩展了吸热参数空间。
中文摘要 AI 辅助
直接探测实验中高能核反冲的解释可能敏感地依赖于银河系暗物质（DM）分布的高速尾部。LUX-ZEPLIN（LZ）实验最近报告了一个事件 LZ230616，其核反冲能量为 248 ± 23（统计）± 23（系统）keV，而 Gaia 任务提供了对银河系运动学和质量分布前所未有的视角。我们将这两种探测手段结合起来，利用从 Gaia 信息约束的银河系模型中推断出的速度分布，研究 LZ230616 的非弹性暗物质解释。与标准晕模型相比，所得分布具有更低的逃逸速度和显著抑制的高速尾部，但局部密度更高。我们发现，虽然放热解释对这种变化基本不敏感，但吸热解释则需要显著更大的散射截面和更小的质量劈裂。此外，利用基于模拟的对大麦哲伦云引力效应的研究，我们表明高速尾部可以将允许的吸热参数空间扩展到更低的暗物质质量和更大的劈裂。我们的结果证明了将暗物质直接探测搜索与银河系动力学精密测量相结合，可以定性影响高能核反冲的粒子物理解释。
英文摘要
The interpretation of high-energy nuclear recoils in direct-detection experiments can depend sensitively on the high-velocity tail of the galactic dark matter (DM) distribution. The LUX-ZEPLIN (LZ) experiment has recently reported an event, LZ230616, with nuclear recoil energy 248 $\pm$ 23 (stat) $\pm$ 23 (sys) keV, while the Gaia mission has provided an unprecedented view of the kinematics and mass distribution of the Milky Way. We bring these two probes together to investigate the inelastic DM interpretation of LZ230616, using a velocity distribution inferred from Gaia-informed galactic model. Compared to the Standard Halo Model, the resulting distribution has a lower escape speed and a significantly suppressed high-velocity tail, with a higher local density. We find that while the exothermic interpretation is largely insensitive to this change, the endothermic interpretation requires substantially larger scattering cross sections and smaller mass splittings. Furthermore, using simulation-based study of the gravitational effects of the Large Magellanic Cloud, we show that the high-velocity tail can extend the allowed endothermic parameter space towards lower DM masses and larger splittings. Our results demonstrate how combining direct searches for DM detection with precision measurements of galactic dynamics can qualitatively affect the particle-physics interpretation of high-energy nuclear recoils.
发表机构
- Saha Institute of Nuclear Physics（萨哈核物理研究所）
- Homi Bhabha National Institute（霍米·巴巴国立学院）
- Tata Institute of Fundamental Research（塔塔基础研究所）
- Indian Institute of Technology Bombay（孟买印度理工学院）
机构由 AI 辅助整理，请以论文原文为准。
