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arXiv 2003.07638hep-phhep-ex
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$U(1)_{e-μ}$模型中的电子和μ子$g-2$、辐射中微子质量和$\ell' \to \ell γ$

Electron and muon $g-2$, radiative neutrino mass, and $\ell' \to \ell γ$ in a $U(1)_{e-μ}$ model

Chuan-Hung Chen, Takaaki Nomura

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24 pages, 7 figures, version accepted for publication in NPB
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摘要：

提出了一个非常规的$U(1)_{e-μ}$规范模型来解释电子和μ子（轻子$g-2$）的反常磁矩，其中在标准模型中只有右手电子和μ子携带$U(1)_{e-μ}$电荷.虽然轻轻子质量在规范对称性自发破缺时被抑制，但它们可以通过汤川耦合到新引入的粒子，如矢量轻子二重态和单重态，以及标量单重态产生。发现同样的Yukawa耦合与新的标量耦合相结合可以诱导辐射轻子味破坏过程$\ell' \to \ell γ$和轻子$g-2$，其中轻子$g-2$正比于$m_{\ell}$ .在模型中加入马约拉纳费米子和标量单态后，活跃中微子可以通过辐射跷跷板机制获得质量。当满足$m_e$和$m_μ$的边界条件和中微子数据时，我们发现电子$g-2$可以达到$-10^{-12}$的数量级，μ子$g-2$可以达到$10^{-9}$的数量级.另外，当抑制$μ\to e γ$衰减时，所得的$τ\to e γ$的分支比可以为$O(10^{-8})$，并且$τ\to μγ$的分支比可以与电流上限一样大。

英文摘要：

A nonconventional $U(1)_{e-μ}$ gauge model is proposed to explain the unexpected anomalous magnetic moments of the electron and muon (lepton $g-2$), where only the right-handed electron and muon in the standard model carry the $U(1)_{e-μ}$ charge. Although the light lepton masses are suppressed when the gauge symmetry is spontaneously broken, they can be generated through the Yukawa couplings to newly introduced particles, such as vector-like lepton doublets and singlet, and scalar singlets. It is found that the same Yukawa couplings combined with the new scalar couplings to the Higgs can induce the radiative lepton-flavor violation processes $\ell' \to \ell γ$ and lepton $g-2$, where the lepton $g-2$ is proportional to $m_{\ell}$. When Majorana fermions and a scalar singlet are further added into the model, the active neutrinos can obtain masses via the radiative seesaw mechanism. When the bounds from the $m_e$ and $m_μ$ and the neutrino data are satisfied, we find that the electron $g-2$ can reach an order of $-10^{-12}$, and the muon $g-2$ can be an order of $10^{-9}$. In addition, when the $μ\to e γ$ decay is suppressed, the resulting branching ratio for $τ\to e γ$ can be of $O(10^{-8})$, and that for $τ\to μγ$ can be as large as the current upper limit.

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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