AI 中文总结
该研究基于TNG50模拟样本发现暗物质晕普遍共转，会影响暗物质直接探测的散射率与截面上限，相关不确定性可通过银河系形成历史研究降低。
AI 中文摘要
宇宙学模拟近期已开始量化太阳周围暗物质相空间分布中的晕间方差。我们使用TNG50模拟中近百个类银河系星系样本，确定该方差的哪些方面控制暗物质直接探测的预测。与标准晕模型假设的各向同性相反，我们发现暗物质的中位方位速度非零且优先共转，即沿重子盘的旋转方向，范围为6-70 km/s（第16至84百分位）。这种共转会抑制寻找轻于50 GeV的暗物质的实验室实验中的预测散射率，并显著影响定向探测器的预期每日调制振幅。尤其，这会在典型的各向同性吨级实验的峰值灵敏度处，对暗物质-核子相互作用截面的上限产生21%的不确定性。不过，该不确定性并非不可约：它与旋转速度强相关。如果对银河系形成历史的研究确定了旋转速度，该天体物理不确定性将降至7%。
英文摘要
Cosmological simulations have recently begun to quantify the halo-to-halo variance in the phase-space distribution of dark matter around the Sun. We use a sample of nearly one hundred Milky Way-like galaxies from the TNG50 simulation to determine what aspects of this variance control the predictions for dark matter direct detection. Contrary to the isotropy assumed in the standard halo model, we find the dark matter median azimuthal velocity is nonzero and preferentially corotating, i.e., in the direction of the baryonic disk's rotation, ranging from 6-70 km/s (16th-84th percentile). This corotation suppresses predicted scattering rates in laboratory experiments searching for dark matter lighter than 50 GeV and significantly affects the expected daily modulation amplitude for directional detectors. In particular, this induces a 21% uncertainty on the upper limit of the dark matter-nucleon interaction cross section at peak sensitivity for a typical isotropic ton-scale experiment. This uncertainty is not irreducible, however: it is strongly correlated with the rotational velocity. If studies of the Milky Way's formation history determine the rotation speed, this astrophysical uncertainty is reduced to 7%.
Comments7 pages, 3 figures; 2 pages of end matter with 4 additional figures. Comments welcome!
