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arXiv 2105.07232hep-phastro-ph.CO
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轴子暗辐射:哈勃张力和超神冈中微子实验

Axion Dark Radiation: Hubble Tension and Hyper-kamiokande Neutrino Experiment

Yuchao Gu, Lei Wu, Bin Zhu

摘要:

在这项工作中,我们研究了一个超对称轴子模型的暗扇区,包括晚衰变的引力子/轴子暗物质和轴子暗辐射。在早期宇宙中,轴子的标量超伴子(saxion)的衰变会产生大量的熵。附加熵不仅可以稀释引力子/轴子暗物质的残余密度,避免宇宙的过封闭,而且可以放松对暴胀后再加热温度$T_{R}$的约束。同时,由介子衰变产生的轴子暗辐射将增加中微子种类$N_{\rm eff}$的有效数量,这有助于降低宇宙学哈勃张力。在宇宙晚期,长寿命的引力子/轴子暗物质的衰变产生了具有MeV量级动能的轴子。我们研究了在中微子实验中通过逆Primakoff过程$a+A \to γ+ A$寻找高能轴子的可能性。

英文摘要:

In this work, we investigate the dark sector of a supersymmetric axion model, consisting of the late-decaying gravitino/axino dark matter and axion dark radiation. In the early universe, the decay of the scalar superpartner of the axion (saxion) will produce a large amount of entropy. The additional entropy can not only dilute the relic density of the gravitino/axino dark matter to avoid overclosing the universe but also relax the constraint on the reheating temperature $T_{R}$ after inflation. Meanwhile, the axion dark radiation from the saxion decay will increase the effective number of neutrino species $N_{\rm eff}$, which can help to reduce the cosmological Hubble tension. In the late universe, the decay of long-lived gravitino/axino dark matter produces the axions with MeV-scale kinetic energy. We study the potential of searching for such energetic axions through the inverse Primakoff process $a+A \to γ+ A$ in the neutrino experiments, such as Hyper-Kamiokande.

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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