We use the latest measurements of the Milky Way satellite population from the Dark Energy Survey and Pan-STARRS1 to infer the most stringent astrophysical bound to date on velocity-dependent interactions between dark matter particles and protons. We model the momentum-transfer cross section as a power law of the relative particle velocity v with a free normalizing amplitude, σ _MT = σ ₀ v ⁿ , to broadly capture the interactions arising within the nonrelativistic effective theory of dark matter–proton scattering. The scattering leads to a momentum and heat transfer between the baryon and dark matter fluids in the early universe, ultimately erasing structure on small physical scales and reducing the abundance of low-mass halos that host dwarf galaxies today. From the consistency of observations with the cold collisionless dark matter paradigm, using a new method that relies on the most robust predictions of the linear perturbation theory, we infer an upper limit on σ ₀ of 1.4 10⁻²³, 2.1 10⁻¹⁹, and 1.0 10⁻¹² cm², for interaction models with n = 2, 4, and 6, respectively, for a dark matter particle mass of 10 MeV. These results improve observational limits on dark matter–proton scattering by orders of magnitude and thus provide an important guide for viable sub-GeV dark matter candidates.

我们使用暗能量调查和 Pan-STARRS1 对银河系卫星群的最新测量结果来推断暗物质粒子和质子之间的速度相关相互作用迄今为止最严格的天体物理学约束。我们将动量传递截面建模为具有自由归一化振幅的相对粒子速度v的幂律，σ _MT = σ ₀ v ⁿ ，以广泛地捕捉暗物质 - 质子散射的非相对论有效理论中产生的相互作用。散射导致早期宇宙中重子和暗物质流体之间的动量和热传递，最终消除了小物理尺度上的结构，并减少了当今矮星系所在的低质量晕的丰度。根据观测与冷无碰撞暗物质范式的一致性，使用依赖于线性微扰理论最稳健预测的新方法，我们推断出σ ₀的上限为 1.4 10 ^-23、2.1 10 ^-19，并且1.0 10 ^-12 cm ²，对于具有n 的交互模型= 2、4 和 6，对于 10 MeV 的暗物质粒子质量。这些结果将暗物质-质子散射的观测限制提高了几个数量级，从而为可行的亚 GeV 暗物质候选者提供了重要指导。