论文标题
$ b_c \ toτν_τ$在CEPC上的分析
Analysis of $B_c \to τν_τ$ at CEPC
论文作者
论文摘要
$ b_c \至τν_τ$分支比率的精确确定为理解标准模型的电动结构提供了有利的机会，测量了CKM矩阵元素$ | v_ {cb} | $并探索新的物理模型。在本文中，我们讨论了在拟议的圆形电子正电子对撞机（CEPC）上用$τ$衰减来测量$ b_c \ toτν_τ$的过程的潜力。我们得出的结论是，在$ z $ pole的操作中，通道信号可以实现五美元的意义，而$ \ sim 10^9 $ $ z $衰变，以及$ b_c \ toτν_τ$的信号强度精度可以达到1％的水平，即标称cepc $ z $ z $ z $ z $ pole $ $ b _ $ b _ $ b_c \ t time 3. 3 3. 10^6 $。我们的理论分析表明，准确性可以对$ b \ tocτν$过渡的一般有效的哈密顿量提供强大的限制。如果可以确定总计$ b_c $的收益率将来确定为$ \ MATHCAL {O}（1 \％）$将来的准确度级别，则这些结果也意味着$ | v_ {cb} | $可以测量最高$ \ nathcal {o}（o}（1 \％）$准确度的准确度。
The precise determination of the $B_c \to τν_τ$ branching ratio provides an advantageous opportunity for understanding the electroweak structure of the Standard Model, measuring the CKM matrix element $|V_{cb}|$ and probing new physics models. In this paper, we discuss the potential of measuring the processes of $B_c \to τν_τ$ with $τ$ decaying leptonically at the proposed Circular Electron Positron Collider (CEPC). We conclude that during the $Z$ pole operation, the channel signal can achieve five $σ$ significance with $\sim 10^9$ $Z$ decays, and the signal strength accuracies for $B_c \to τν_τ$ can reach around 1% level at the nominal CEPC $Z$ pole statistics of one trillion $Z$ decays assuming the total $B_c \to τν_τ$ yield is $3.6 \times 10^6$. Our theoretical analysis indicates the accuracy could provide a strong constraint on the general effective Hamiltonian for the $b \to cτν$ transition. If the total $B_c$ yield can be determined to $\mathcal{O}(1\%)$ level of accuracy in the future, these results also imply $|V_{cb}|$ could be measured up to $\mathcal{O}(1\%)$ level of accuracy.
