发表机构
University of Arizona; Tata Institute of Fundamental Research（亚利桑那大学; 塔塔基础研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用DESI光谱叠加搜索多态暗物质的磁偶极吸收线，在145,087条光谱中未发现信号，给出2σ截面上限，并预测未来巡天可将限制提高一个数量级。
AI 中文摘要
我们通过背景源光谱中的吸收线来搜寻暗物质，这些背景源的视线穿过前景暗物质晕。这种吸收线是多态暗物质模型的一个普遍特征，该模型中暗物质通过高阶电磁矩与光子耦合。我们聚焦于具有磁偶极跃迁的两态系统的最小情形，其中基态吸收一个光子并跃迁到激发态。对于跃迁能量$\Delta E \sim O \\,(\text{eV})$，该吸收线落在光学波段，处于DESI等光谱巡天的可达范围内。通过叠加145,087条DESI早期数据发布中与前景GAMA星系群配对的光谱，我们发现叠加后的光学深度与零一致，并对磁偶极跃迁截面给出了$2\sigma$上限。这些限制在$\Delta E \sim$ 3-5 eV、暗物质质量为数MeV的参数空间中最为严格，该参数空间是宇宙学（BBN+CMB）和直接探测实验均无法触及的。我们预测，完整的DESI以及下一代光谱巡天将把这些限制提高一个数量级以上，从而使光谱叠加成为探测电磁相互作用多态暗物质的有力手段。
英文摘要
We search for dark matter through absorption lines imprinted on the spectra of background sources whose sightlines pass through foreground dark matter halos. Such a line is a generic feature of multi-state dark matter models that couple to photons through higher-order electromagnetic moments. We focus on the minimal case of a two-state system with a magnetic dipole transition, in which the ground state absorbs a photon and makes a transition to the excited state. For transition energy $ΔE \sim O \,(\text{eV})$, the line falls in the optical band, within reach of spectroscopic surveys such as DESI. Stacking 145,087 spectra of DESI Early Data Release objects paired with foreground GAMA galaxy groups, we find a stacked optical depth consistent with zero and place $2σ$ upper limits on the magnetic dipole transition cross-section. The limits are strongest at $ΔE \sim$ 3-5 eV for a few MeV dark matter mass in the parameter space that is inaccessible to both cosmological (BBN+CMB) and direct detection experiments. We forecast that the full DESI and the next-generation spectroscopic surveys will tighten these limits by more than an order of magnitude, establishing spectroscopic stacking as a competitive probe of electromagnetically interacting multi-state dark matter.
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