Astrophysical observations spanning dwarf galaxies to galaxy clustersindicate that dark matter (DM) halos are less dense in their central regionscompared to expectations from collisionless DM N-body simulations. Usingdetailed fits to DM halos of galaxies and clusters, we show thatself-interacting DM (SIDM) may provide a consistent solution to the DM deficitproblem across all scales, even though individual systems exhibit a widediversity in halo properties. Since the characteristic velocity of DM particlesvaries across these systems, we are able to measure the self-interaction crosssection as a function of kinetic energy and thereby deduce the SIDM particlephysics model parameters. Our results prefer a mildly velocity-dependent crosssection, from $\sigma/m \simeq 2\; {\rm cm^2/g}$ on galaxy scales to $\sigma/m\simeq 0.1\; {\rm cm^2/g}$ on cluster scales, consistent with the upper limitsfrom merging clusters. Our results dramatically improve the constraints on SIDMmodels and may allow the masses of both DM and dark mediator particles to bemeasured even if the dark sector is completely hidden from the Standard Model,which we illustrate for the dark photon model.
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机译:横跨矮星系到星系团的天体观测表明,与无碰撞DM N体模拟的预期相比,暗物质(DM)晕在其中心区域密度较小。使用对星系和星团的DM光晕的详细拟合,我们证明了自相互作用DM(SIDM)可以为所有尺度上的DM缺陷问题提供一致的解决方案,即使单个系统在光晕特性方面表现出很大的差异。由于DM颗粒的特征速度在这些系统中会发生变化,因此我们能够测量自相互作用横截面随动能的变化,从而得出SIDM颗粒物理模型参数。我们的结果更喜欢一个与速度有关的温和截面,从$ \ sigma / m \ simeq 2 \; {\ rm cm ^ 2 / g} $(在星系上缩放为$ \ sigma / m \ simeq 0.1 \); {\ rm cm ^ 2 / g} $在集群规模上,与合并集群的上限一致。我们的结果极大地改善了对SIDM模型的约束,并且即使暗区完全隐藏在标准模型中(我们为暗光子模型说明),也可以测量DM和暗介体颗粒的质量。
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