Primordial black holes from QCD axion bubbles
Primordial black holes from QCD axion bubbles
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DOI：
10.1088/1475-7516/2020/11/060
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发表时间：
2020-06
影响因子：
6.4
通讯作者：
N. Kitajima;F. Takahashi
中科院分区：
文献类型：
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作者：
N. Kitajima;F. Takahashi
我们提出了一个方案，其中一个强大的Peccei-Quinn（PQ）对称性破缺在早期宇宙中的初始QCD轴子场值的大的不均匀性的结果，导致非常密集的轴子泡的形成。一些轴子泡随后坍缩成原始黑洞（PBH）。QCD轴子的空间均匀部分解释了宇宙的暗物质，而轴子泡产生的PBH可以解释LIGO事件或超大质量黑洞的种子。有趣的是，PBH的质量是由轴子衰变常数决定的;当fa = 1017（1016）GeV时，PBH的质量比10（104）M重。此外，轴子微团簇也是由轴子气泡形成的，比PBH更丰富，并且它们的质量预计会比基于膨胀后PQ对称性自发破缺的通常情况下更重。
We propose a scenario in which a strong Peccei-Quinn (PQ) symmetry breaking in the early universe results in large inhomogeneities of the initial QCD axion field value, leading to the formation of very dense axion bubbles. Some of the axion bubbles subsequently collapse into primordial black holes (PBHs). The spatially homogeneous part of the QCD axion explains dark matter of the universe, while the PBHs arising from the axion bubbles can explain the LIGO events or the seed of supermassive black holes. Interestingly, the mass of PBH is determined by the axion decay constant; for fa = 1017 (1016) GeV, the PBH mass is heavier than about 10 (104) M⊙. In addition, axion miniclusters are also formed from the axion bubbles more abundantly than PBHs, and their masses are expected to be heavier than in the usual scenario based on the spontaneous breaking of the PQ symmetry after inflation.