Dark matter from decaying topological defects
Dark matter from decaying topological defects
复制标题
衰变拓扑缺陷产生的暗物质
DOI：
10.1088/1475-7516/2014/03/037
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发表时间：
2014
影响因子：
6.4
通讯作者：
Hindmarsh M
中科院分区：
文献类型：
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作者：
Hindmarsh M
我们研究暗物质的生产衰变的拓扑缺陷，特别是宇宙弦。在拓扑缺陷或“自上而下”（TD）的情况下，暗物质注入率随时间呈幂律变化，指数为p− 4。我们找到了一个封闭形式的公式，用于计算所有p< 3/2的产率，它精确地再现了玻尔兹曼方程的解。我们调查了两个方案（p= 1，p= 7/6）的动机宇宙弦衰变到TeV尺度的状态与高分支分数到暗物质粒子。对于暗物质模型湮灭无论是由s-波或p-波，我们发现的TD模型可以占暗物质遗迹密度普朗克测量的参数空间的区域。我们发现，拓扑缺陷可以是暗物质的主要来源，即使标准的冻结计算低于预测的遗迹密度，因此可以导致潜在的大的“助推因子”增强暗物质湮灭率。我们研究暗物质模型独立的限制，这种情况下所产生的幺正性和讨论的例子模型依赖的限制来自间接的暗物质搜索实验。在研究的四种情况中，具有进入TeV尺度状态的明显通道的弦的Gμ上限比当前的宇宙微波背景限制严格得多。
We study dark matter production by decaying topological defects, in particular cosmic strings. In topological defect or``top-down''(TD) scenarios, the dark matter injection rate varies as a power law with time with exponent p− 4. We find a formula in closed form for the yield for all p< 3/2, which accurately reproduces the solution of the Boltzmann equation. We investigate two scenarios (p= 1, p= 7/6) motivated by cosmic strings which decay into TeV-scale states with a high branching fraction into dark matter particles. For dark matter models annihilating either by s-wave or p-wave, we find the regions of parameter space where the TD model can account for the dark matter relic density as measured by Planck. We find that topological defects can be the principal source of dark matter, even when the standard freeze-out calculation under-predicts the relic density and hence can lead to potentially large``boost factor''enhancements in the dark matter annihilation rate. We examine dark matter model-independent limits on this scenario arising from unitarity and discuss example model-dependent limits coming from indirect dark matter search experiments. In the four cases studied, the upper bound on Gμ for strings with an appreciable channel into TeV-scale states is significantly more stringent than the current Cosmic Microwave Background limits.