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arXiv 1609.03569astro-ph.COhep-ph
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部分声学暗物质、相互作用的暗辐射和大尺度结构

Partially Acoustic Dark Matter, Interacting Dark Radiation, and Large Scale Structure

Zackaria Chacko, Yanou Cui, Sungwoo Hong, Takemichi Okui, Yuhsin Tsai

备注：
10 pages, 3 figures; matches version published in JHEP
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摘要：

无碰撞的冷暗物质的标准范例与大尺度的测量存在矛盾。特别是，从宇宙微波背景中推断的哈勃率$H_0$和物质密度扰动$σ_8$的最佳拟合值似乎与直接测量的结果不一致。我们表明，这两个问题都可以解决的框架中，暗物质由两个不同的组件，一个主导组件和次主导组件。主要成分是冷的和无碰撞的。次级成分也是冷的，但与暗辐射强烈相互作用，暗辐射本身形成紧密耦合的流体。在次优势分量的密度扰动的增长被抑制暗声振荡，由于其耦合到暗辐射，解决了$σ_8$问题，而紧耦合的暗辐射的存在改善了$H_0$问题。暗物质和暗辐射的次主导成分继续保持热平衡，直到晚期，抑制了暗盘的形成。我们提出了一个简单的模型，自然实现这种情况下，两个组成部分的暗物质热WIMP的例子。我们的方案可以通过未来的第四阶段实验进行测试，旨在探测CMB和大尺度结构。

英文摘要：

The standard paradigm of collisionless cold dark matter is in tension with measurements on large scales. In particular, the best fit values of the Hubble rate $H_0$ and the matter density perturbation $σ_8$ inferred from the cosmic microwave background seem inconsistent with the results from direct measurements. We show that both problems can be solved in a framework in which dark matter consists of two distinct components, a dominant component and a subdominant component. The primary component is cold and collisionless. The secondary component is also cold, but interacts strongly with dark radiation, which itself forms a tightly coupled fluid. The growth of density perturbations in the subdominant component is inhibited by dark acoustic oscillations due to its coupling to the dark radiation, solving the $σ_8$ problem, while the presence of tightly coupled dark radiation ameliorates the $H_0$ problem. The subdominant component of dark matter and dark radiation continue to remain in thermal equilibrium until late times, inhibiting the formation of a dark disk. We present an example of a simple model that naturally realizes this scenario in which both constituents of dark matter are thermal WIMPs. Our scenario can be tested by future stage-IV experiments designed to probe the CMB and large scale structure.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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