标题： 黑暗维度与衰变的暗物质引力子 显示英文标题

标题： Dark Dimension and Decaying Dark Matter Gravitons

摘要： 我们研究了暗维度情景的宇宙学，并考虑了线性扰动的影响。 在暗维度情景的背景下，我们宇宙中的暗物质自然候选者是大量具有大质量自旋-2 Kaluza-Klein（KK）引力子激发态。 这些暗引力子在早期宇宙中产生，并在宇宙学演化过程中衰变为较轻的KK引力子。 这种衰变导致暗物质的平均质量随着宇宙的演化而减小。 此外，每次衰变释放出的动能会导致暗物质粒子获得一个踢动速度，从而抑制结构形成。 利用当前的CMB（普朗克）、BAO和宇宙剪切（KiDS-1000）数据，我们在95%置信水平下对今天暗物质的踢动速度$v_\mathrm{today} \leq 2.2 \times 10^{-4} c$进行了限制。 这导致暗维度情景的参数空间出现相当特定的区域。 宇宙学、天体物理学和桌面实验的实验限制组合得出暗维度大小的范围$l_5\sim 1- 10 \, \mu m$。 发现暗维度情景与当前观测结果非常一致，并提供了近未来实验可探测到的特征。 显示英文摘要

摘要： We explore the cosmology of the Dark Dimension scenario taking into account perturbations in the linear regime. In the context of the Dark Dimension scenario, a natural candidate for dark matter in our universe is the excitations of a tower of massive spin-2 KK gravitons. These dark gravitons are produced in the early universe and decay to lighter KK gravitons during the course of cosmological evolution. The decay causes the average dark matter mass to decrease as the universe evolves. In addition, the kinetic energy liberated in each decay leads to a kick velocity for the dark matter particles leading to a suppression of structure formation. Using current CMB (Planck), BAO and cosmic shear (KiDS-1000) data, we put a bound on the dark matter kick velocity today $v_\mathrm{today} \leq 2.2 \times 10^{-4} c$ at 95\% CL. This leads to rather specific regions of parameter space for the dark dimension scenario. The combination of the experimental bounds from cosmology, astrophysics and table-top experiments lead to the range $l_5\sim 1- 10 \, \mu m$ for the size of the Dark Dimension. The Dark Dimension scenario is found to be remarkably consistent with current observations and provides signatures that are within reach of near-future experiments.