Cosmic axion background
Cosmic axion background
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DOI：
10.1103/physrevd.103.115004
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发表时间：
2021-06-07
影响因子：
5
通讯作者：
Rodd, Nicholas L.
中科院分区：
文献类型：
--
作者：
Dror, Jeff A.;Murayama, Hitoshi;Rodd, Nicholas L.
现有的对宇宙轴子遗迹的搜索在很大程度上依赖于轴子是非相对论的，并且构成了暗物质。然而，光轴子可以在早期宇宙中大量产生，并在今天保持相对论，从而构成宇宙轴子背景(CAB)。作为轴子源的典型例子，我们考虑了热产生、暗物质衰变、参数共振和拓扑缺陷衰变。其中每一个都有一个特征频谱，可以在轴子直接探测实验中搜索到。我们把重点放在轴子-光子耦合上，并研究了当前和未来版本的ADMX、Haystac、DMRadio和Abracadabra对驾驶室的敏感性，发现在寻找暗物质时收集的数据可以被重新用于检测轴子能量密度，远远低于宇宙能量收支测量设置的极限。通过这种方式，直接探测相对论遗迹提供了一个强大的新机会来了解早期宇宙，并有可能发现轴子。
Existing searches for cosmic axions relics have relied heavily on the axion being nonrelativistic and making up dark matter. However, light axions can be copiously produced in the early Universe and remain relativistic today, thereby constituting a Cosmic axion Background (CaB). As prototypical examples of axion sources, we consider thermal production, dark-matter decay, parametric resonance, and topological defect decay. Each of these has a characteristic frequency spectrum that can be searched for in axion direct detection experiments. We focus on the axion-photon coupling and study the sensitivity of current and future versions of ADMX, HAYSTAC, DMRadio, and ABRACADABRA to a CaB, finding that the data collected in search of dark matter can be repurposed to detect axion energy densities well below limits set by measurements of the energy budget of the Universe. In this way, direct detection of relativistic relics offers a powerful new opportunity to learn about the early Universe and, potentially, discover the axion.