Contributions of the W-boson propagator to $\mu$ and $\tau$ leptonic decay rates
Contributions of the W-boson propagator to $\mu$ and $\tau$ leptonic decay rates
复制标题
W 玻色子传播子对 $mu$ 和 $ au$ 轻子衰变率的贡献
DOI：
10.1103/physrevd.88.033012
复制
发表时间：
2013
影响因子：
5
通讯作者：
Zhibai Zhang
中科院分区：
文献类型：
--
作者：
A. Ferroglia;C. Greub;A. Sirlin;Zhibai Zhang
我们得到了树能级W玻色子传播子对μ介子和τ介子轻子衰变率贡献的封闭表达式和有用的展开式。我们把M和m称为初始和末态带电轻子的质量，因此我们在极限m=0时的结果对M^2/M_W^2中的所有阶都是有效的。在O（m_j^2/M_W^2）（m_j=M，m）的条件下，我们的首项修正O（M^2/M_W^2）与正则值（3/5）M^2/M_W^2一致，而次首项修正系数O（m^2/M_W^2）与最近文献报道的结果不同。一个可能的解释的差异。简要讨论了O（m_j^2/M_W^2）修正的数值效应。附录中给出了一个对M_W>M>m范围内的M_W、M和m的任意值都有效的一般表达式。本文还回顾了费米常数的传统定义和计算方法。
We derive closed expressions and useful expansions for the contributions of the tree-level W-boson propagator to the the muon and tau leptonic decay rates. Calling M and m the masses of the initial and final charged leptons, our results in the limit m=0 are valid to all orders in M^2/M_W^2. In the terms of O(m_j^2/M_W^2) (m_j=M,m), our leading corrections, of O(M^2/M_W^2), agree with the canonical value (3/5) M^2/M_W^2, while the coefficient of our subleading contributions, of O(m^2/M_W^2), differs from that reported in the recent literature. A possible explanation of the discrepancy is presented. The numerical effect of the O(m_j^2/M_W^2) corrections is briefly discussed. A general expression, valid for arbitrary values of M_W, M and m in the range M_W>M>m, is given in the Appendix. The paper also contains a review of the traditional definition and evaluation of the Fermi constant.