We show that dark matter direct detection experiments are sensitive to the existence of particles with a small effective charge (for instance, via couplings to a kinetically mixed, low-mass dark photon). Our forecasts do depend on these particles comprising a significant fraction of the dark matter. Rather, these experiments are sensitive to the irreducible abundance produced in the early Universe through the freeze-in mechanism. We find that ongoing and proposed direct detection experiments will have world-leading sensitivity to effective charges Q∼10−12 across 9 orders of magnitude in mass, corresponding to a dark matter subfraction as low as ∼10−3. Published by the American Physical Society 2025

中文翻译：

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暗物质直接检测实验对毫电荷背景敏感


我们表明，暗物质直接探测实验对有效电荷小的粒子的存在很敏感（例如，通过与动力学混合的低质量暗光子耦合）。我们的预测确实依赖于这些粒子，它们占暗物质的很大一部分。相反，这些实验对早期宇宙中通过冻结机制产生的不可还原的丰度很敏感。我们发现，正在进行和拟议的直接检测实验对质量 9 个数量级的有效电荷 Q∼10-12 具有世界领先的灵敏度，对应于低至 ∼10-3 的暗物质亚级分。美国物理学会 2025 年出版