Search for new physics in semileptonic $B$-decays
Search for new physics in semileptonic $B$-decays
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DOI：
10.22323/1.282.0568
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发表时间：
2016-11
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影响因子：
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通讯作者：
Suzanne Klaver
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文献类型：
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作者：
Suzanne Klaver
半轻子衰变是检验标准模型（SM）的绝佳环境。轻子普适性的破坏将是超出标准模型的新物理的有力证据。通过半陶轻子 $B$ 衰变，大型强子对撞机底夸克实验（LHCb）测得 $\mathcal{R}(D^*) = \mathcal{B}(\overline{B}^0 \to D^{*+} \tau^- \overline{\nu}_{\tau})/\mathcal{B}(\overline{B}^0 \to D^{*+} \mu^- \overline{\nu}_{\mu}) = 0.336 \pm 0.027 \text{(统计误差)} \pm 0.030 \text{(系统误差)}$，这比标准模型预期值高出2.1个标准差。此外，$B_s^0$ 介子混合中的电荷宇称（$C\!P$）不对称性测量对超出标准模型的新物理高度敏感。本文给出了半轻子不对称性的最新结果；利用第一轮运行的全部数据集，发现 $a_{\rm{sl}}^s = (0.39 \pm 0.26 \text{(统计误差)} \pm 0.20 \text{(系统误差)})\%$，这与标准模型相符。
Semileptonic decays provide an excellent environment for testing the Standard Model (SM). Violation of lepton universality would be a smoking gun for physics beyond the SM. Using semi-tauonic $B$ decays, LHCb finds a value of $\mathcal{R}(D^*) = \mathcal{B}(\overline{B}^0 \to D^{*+} \tau^- \overline{\nu}_{\tau})/\mathcal{B}(\overline{B}^0 \to D^{*+} \mu^- \overline{\nu}_{\mu}) = 0.336 \pm 0.027 \rm{(stat)} \pm 0.030 \rm{(syst)}$, which is 2.1 standard deviations larger than the value expected from the SM. Moreover, the measurement of the $C\!P$ asymmetry in mixing of $B_s^0$ mesons is highly sensitive to physics beyond the SM. This article presents the latest result on semileptonic asymmetries; using the full Run 1 dataset, it is found that $a_{\rm{sl}}^s = (0.39 \pm 0.26 \rm{(stat)} \pm 0.20 \rm{(syst)})\%$, which is consistent with the Standard Model.