The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the $\mu \tau$ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the $\tau$ mass enhancement in the one-loop correction. In this paper, we study the signal of this model, i.e. the same-sign leptons, in the Belle II experiment, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensitive to the scenario in the mediator mass range of ${\cal O}(1-10)$~GeV, using the $e^+e^- \to \mu^\pm\tau^\mp X \to\mu^\pm \mu^\pm \tau^\mp \tau^\mp$ process induced by the $X$.

中文翻译：

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在 Belle II 探索 μτ 风味违反解决方案的 μon g − 2 异常

μ子异常磁矩的测量值与标准模型预测之间的差异是粒子物理学中最重要的问题之一。众所周知，由于单环校正中的 $\tau$ 质量增强，引入具有 $\mu\tau$ 轻子风味违反 (LFV) 耦合的介体玻色子 X 是解释这种差异的一个很好的解决方案。在本文中，我们在 Belle II 实验中研究该模型的信号，即同号轻子，假设风味对角线耦合被抑制。我们表明，Belle II 实验对介体质量范围 ${\cal O}(1-10)$~GeV 中的场景高度敏感，使用 $e^+e^- \to \mu^\pm \tau^\mp X \to\mu^\pm \mu^\pm \tau^\mp \tau^\mp$ 过程由 $X$ 引起。