论文标题
了解$ S_8 $张力的一步
A Step in Understanding the $S_8$ Tension
论文作者
论文摘要
具有质量阈值的黑暗部门模型可以具有重要的宇宙学特征。如果在重组之前的时代，相对论物种变为非宗派主义，然后在平衡中减少人口，则随着熵转移到较轻的相对主义颗粒，可能会对宇宙微波背景产生可测量的影响。特别是，如果此``步骤''发生在$ z \ sim 20,000 $附近，则该型号自然可以容纳$ h_0 $的较大值。如果此阶梯辐射还与暗物质相结合，则可能会对物质的功率谱产生有意义的影响，因为暗物质可以通过变为非率主义和耗尽的物种耦合。这自然会导致台阶前声音范围内的尺度抑制功率，同时留下传统的冷暗物质签名，以便在声音范围之外进行电源。我们研究这些效果，并表明这种模型自然可以提供$ s_8 $的值，而没有步骤。这表明这些模型可能会提供一个有趣的框架来解决$ s_8 $张力，包括与$ h_0 $张力以及不使用。
Models of dark sectors with a mass threshold can have important cosmological signatures. If, in the era prior to recombination, a relativistic species becomes nonrelativistic and is then depopulated in equilibrium, there can be measurable impacts on the cosmic microwave background as the entropy is transferred to lighter relativistic particles. In particular, if this ``step'' occurs near $z\sim 20,000$, the model can naturally accommodate larger values of $H_0$. If this stepped radiation is additionally coupled to dark matter, there can be a meaningful impact on the matter power spectrum as dark matter can be coupled via a species that becomes nonrelativistic and depleted. This can naturally lead to suppressed power at scales inside the sound horizon before the step, while leaving conventional cold dark matter signatures for power outside the sound horizon. We study these effects and show such models can naturally provide lower values of $S_8$ than scenarios without a step. This suggests these models may provide an interesting framework to address the $S_8$ tension, both in concert with the $H_0$ tension and without.
