CEPC的$B_c \to τν_τ$分析
Analysis of $B_c \to τν_τ$ at CEPC
摘要：
$B_c \to τν_τ$分支比的精确测定为理解标准模型的电弱结构、测量CKM矩阵元$|V_{cb}|$和探索新的物理模型提供了有利的机会。本文讨论了在环形正负电子对撞机上测量$B_c \to τν_τ$与$τ$轻子衰变过程的可能性。我们的结论是，在$Z$极点操作，信道信号可以实现5 $σ$意义与$\sim 10^9$ $Z$衰变，和$B_c \to τν_τ$的信号强度精度可以达到约1%的水平，在名义CEPC $Z$极点统计的一万亿$Z$衰变假设总$B_c \to τν_τ$产量是$3.6 \times 10^6$。我们的理论分析表明，精度可以提供一个强有力的约束的一般有效的哈密顿量的$b \to cτν$过渡。如果将来可以将$B_c$总产率确定为$\mathcal{O}(1\%)$准确度水平，则这些结果也意味着可以将$|V_{cb}|$测量为高达$\mathcal{O}(1\%)$准确度水平。
英文摘要：
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.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
