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arXiv 1810.01889hep-phphysics.atom-ph
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相干弛豫暗物质

Coherent relaxion dark matter

Abhishek Banerjee, Hyungjin Kim, Gilad Perez

备注：
8 pages, 1 figure; v2 matches version accepted by PRD, previously ignored effect included, available parameter space shifted, discussion extended
发表信息：
Phys. Rev. D 100, 115026 (2019)
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摘要：

我们表明，弛豫，解决层次问题，可以解释所观察到的暗物质（DM）遗迹密度。设置是类似的情况下，轴子DM模型顶部的动态失调机制。再加热后，当温度远高于电弱标度时，反反应势消失，弛豫从真空中被取代。当“摆动”再次出现时，弛豫相干振荡在其最小值附近，就像香草轴子DM模型的情况一样。我们确定的参数空间，使弛豫被重新捕获导致标准的宇宙学。当弛豫比$10^{-7}\,$ eV轻时，辐射支配期间的哈勃摩擦足够强以进行再俘获，并且甚至发现极小模型是可行的。这也导致了对弛豫模型的新约束，因为它们的参数空间的某个区域可能导致过多的弛豫DM。或者，甚至更大的参数空间存在时，额外的摩擦是通过从额外的耦合到一个额外的暗光子场的粒子生产。这类模型的现象学是非常独特的，因为它意味着我们被一个依赖于时间的类轴子场所包围，由于弛豫-希格斯混合，这意味着依赖于时间的希格斯真空期望值，导致自然界所有耦合常数随时间变化。

英文摘要：

We show that relaxion, that addresses the hierarchy problem, can account for the observed dark matter (DM) relic density. The setup is similar to the case of axion DM models topped with a dynamical misalignment mechanism. After the reheating, when the temperature is well above the electroweak scale, the backreaction potential disappears and the relaxion is displaced from its vacuum. When the "wiggles" reappear the relaxion coherently oscillates around its minimum as in the case of vanilla axion DM models. We identify the parameter space such that the relaxion is retrapped leading to the standard cosmology. When the relaxion is lighter than $10^{-7}\,$eV, Hubble friction during radiation-domination is sufficiently strong for retrapping, and even minimal models are found to be viable. It also leads to a new constraint on relaxion models, as a certain region of their parameter space could lead to overabundant relaxion DM. Alternatively, even a larger parameter space exists when additional friction is obtained by particle production from additional coupling to an additional dark photon field. The phenomenology of this class of models is quite unique, as it implies that we are surrounded by a time-dependent axion-like field that due to relaxion-Higgs mixing implies time-dependent Higgs vacuum-expectation-value that lead to time-variation of all coupling constants of nature.

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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