AI 中文总结
研究暗物质探测器设计中对称性的作用，通过将暗物质 - 电子散射形状因子分解，把晶体空间群分类，应用对称性投影框架于分子晶体，得出日调制信号损失估计器，可线性估计调制信号大小，实现材料快速筛选。
AI 中文摘要
各向异性材料成为下一代亚GeV暗物质直接探测实验的有前途候选者，因其固有方向性会随探测器相对于暗物质风旋转产生日调制信号。预测调制信号形状需了解电子激发态，但本文表明仅利用材料对称性就能估计调制幅度。通过将有限动量暗物质 - 电子散射形状因子分解为球谐函数，230个晶体空间群缩减为5类。将对称性投影框架应用于分子晶体特殊情况，得出因结晶导致日调制信号损失的精确群论估计器，该估计器仅取决于晶体中分子的对称性和相对取向。最后证明这些估计与调制信号绝对大小成线性比例，无需昂贵电子结构计算就能对分子晶体排序。这些结果为大规模筛选用于定向暗物质探测的各向异性材料提供了快速且可解释的途径。
英文摘要
Anisotropic materials have emerged as promising candidates for the next generation of sub-GeV dark matter direct detection experiments, because their intrinsic directionality gives rise to a daily modulation signal as the detector rotates with respect to a dark matter wind. Predicting the shape of the modulation signal requires knowledge of the electronic excited states: however, we show that the amplitude of the modulation can be estimated using only the symmetries of the material. By decomposing the finite momentum dark matter--electron scattering form factor into spherical harmonics, we show that the 230 crystallographic space groups collapse to just 5 classes, distinguished by their suppression of the quadrupole modes of the squared form factor. We apply our symmetry-projection framework to the special case of molecular crystals, and derive an accurate group-theoretic estimator for the loss of daily modulation signal due to crystallisation, which depends only on the symmetries and relative orientations of the molecules within the crystal. Finally, we demonstrate that these estimates are linearly proportional to the absolute magnitude of the modulation signal, allowing us to rank molecular crystals without the need for expensive electronic structure calculations. Together, these results provide a fast and interpretable route to large-scale screening of anisotropic materials for directional dark matter detection.
Comments63 pages, 15 figures, 4 tables
