ournal of C osmology and A stroparticle hysics J Dark matter from decaying topological defects
ournal of C osmology and A stroparticle hysics J Dark matter from decaying topological defects
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宇宙学杂志和 A 粒子物理学杂志 J 衰变拓扑缺陷中的暗物质
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通讯作者：
M. G. Lillie
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作者：
S. B. Mohanty;A. Ingling;M. G. Lillie
。我们通过衰变的拓扑缺陷，特别是宇宙弦来研究暗物质的产生。在拓扑缺陷或“自上而下”(TD)的情况下，暗物质注入速率随时间呈幂函数变化，指数为p−4。我们fi找到了一个封闭形式的p<；3/2产额公式，它准确地再现了玻尔兹曼方程的解。我们研究了两种情况(p=1，p=7/6)，它们是由宇宙弦激发的，它们衰变到TeV尺度的态，并具有高分支成暗物质粒子的比例。对于被S波和p波湮没的暗物质模型，我们给出了fi模型可以解释普朗克测量的暗物质遗迹密度的参数空间区域。我们fi发现，拓扑缺陷可能是暗物质的主要来源，即使标准的冻结计算低估了遗迹密度，因此可能导致暗物质湮灭率的潜在巨大的“助推因子”增强。我们研究了这种情况下由一元性引起的与暗物质模型无关的极限，并讨论了来自间接暗物质搜索实验的与模型有关的极限的例子。在所研究的四种情况下，具有明显通道进入TeV标度态的弦的Gµ的上限明显比当前的宇宙微波本底限制严格得多。fi
. 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.