标题： B介子寿命和混合参数的数值更新 显示英文标题

标题： Numerical updates of lifetimes and mixing parameters of B mesons

摘要： 我们更新了与$B_s - \bar B_s$和$B_d - \bar B_d$混合相关的几个量的标准模型预测。 $B_s$系统中的质量差和宽度差分别为$ \Delta M_s^{\rm SM} = (17.3 \pm 2.6) ps^{-1}$和$\Delta \Gamma_s^{\rm SM}= (0.087 \pm 0.021) ps^{-1}$。 特定味衰变中的CP不对称性分别为$a_{\rm fs}^{s,\rm SM} = (1.9 \pm 0.3) \cdot 10^{-5}$和$a_{\rm fs}^{d,\rm SM} = - (4.1 \pm 0.6) \cdot 10^{-4}$。 我们进一步批判性地讨论了$\Delta \Gamma_d$对新物理的敏感性以及$\Delta \Gamma_s$与$B_s \to D_s^{(*)}{}^+ D_s^{(*)}{}^-$的分支比之间的不确定性。 然后我们展示了在$B_s$系统中平均宽度$\Gamma_s$的数值更新，并将$\Gamma_s$与$B^+$-$B_d$的寿命比相关联。 最后，我们总结了与 CKMfitter 合作组近期全球分析的关键结果，涉及$B - \bar B$-混合中的新物理。 在通过两个复参数$\Delta_d$和$\Delta_s$对$B - \bar B$混合中的新物理进行适当定义的场景中，标准模型点{$\Delta_d=\Delta_s=1$}被3.6个标准偏差所不支持。 显示英文摘要

摘要： We update the Standard-Model predictions for several quantities related to $B_s - \bar B_s$ and $B_d - \bar B_d$ mixing. The mass and width differences in the $B_s$ system read $ \Delta M_s^{\rm SM} = (17.3 \pm 2.6) ps^{-1}$ and $\Delta \Gamma_s^{\rm SM}= (0.087 \pm 0.021) ps^{-1}$, respectively. The CP asymmetries in flavour-specific decays are $a_{\rm fs}^{s,\rm SM} = (1.9 \pm 0.3) \cdot 10^{-5}$ and $a_{\rm fs}^{d,\rm SM} = - (4.1 \pm 0.6) \cdot 10^{-4}$. We further critically discuss the sensitivity of $\Delta \Gamma_d$ to new physics and the uncertainties in the relation between $\Delta \Gamma_s$ and the branching fraction of $B_s \to D_s^{(*)}{}^+ D_s^{(*)}{}^-$. Then we present a numerical update of the average width $\Gamma_s$ in the $B_s$ system and correlate $\Gamma_s$ with the $B^+$-$B_d$ lifetime ratio. Finally we summarise the key results of our recent global analysis with the CKMfitter collaboration addressing new physics in $B - \bar B$-mixing. In an appropriately defined scenario parametrising new physics in $B - \bar B$-mixing by two complex parameters $\Delta_d$ and $\Delta_s$ the Standard-Model point {$\Delta_d=\Delta_s=1$} is disfavoured by 3.6 standard deviations.