论文标题
$ \ bar {b} _ {（s）}^0 \ to d _ {（s）}^{（*）+} \lbraceπ^ - ，k^ - \ rbrace $衰减和提取$ f_s/f_d $ fragmentation-fractation-fractionation-fractionation-fractionation-fractional分数
A puzzle in $\bar{B}_{(s)}^0 \to D_{(s)}^{(*)+} \lbrace π^-, K^-\rbrace$ decays and extraction of the $f_s/f_d$ fragmentation fraction
论文作者
论文摘要
我们为HADRONIC衰变提供了更新的预测，$ \ bar {b} _s^0 \至d_s^{（*）+}+}π^ - $和$ \ bar {b}^0 \ to d^{（*）+}+} k^ - $。它们基于$ \ MATHCAL {O}（α_s^2）$ $ qcd分解幅度的结果，以及$ \ bar {b} _ {（s）} \ to d _ {（s）}^{（s）}^{（*）} $ form $ { QCD}^2/m_c^2）$在夸克扩展中。我们对矩阵元素进行定量估计，以$ {\ cal o}（λ_{\ rm QCD}/m_b）$以$ {\ cal o}的顺序输入HADRONIC衰减振幅。我们的结果非常精确，并发现理论预测与实验测量之间存在很大的差异。我们探讨了这种差异的两种可能性：比QCD分解功率计数所预测的不可分割的贡献，以及超出标准模型的贡献。我们确定了两种情况的CDF，D0和LHCB实验的$ f_s/f_d $片段分数。
We provide updated predictions for the hadronic decays $\bar{B}_s^0\to D_s^{(*)+} π^-$ and $\bar{B}^0\to D^{(*)+} K^-$. They are based on $\mathcal{O}(α_s^2)$ results for the QCD factorization amplitudes at leading power and on recent results for the $\bar{B}_{(s)} \to D_{(s)}^{(*)}$ form factors up to order ${\cal O}(Λ_{\rm QCD}^2/m_c^2)$ in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order ${\cal O}(Λ_{\rm QCD}/m_b)$ for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the $f_s/f_d$ fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.
