Λ_(b)→Λτ^(+)τ^(-)衰变过程新物理理论  

New Physical Theory of Λ_(b)→Λτ^(+)τ^(-) Decay Process

作　　者：刘文凤 李营 LIU Wen-feng;LI Ying(School of physics and Electronic Information,Yantai University,Yantai 264005,China)

机构地区：[1]烟台大学物理与电子信息学院,山东烟台264005

出　　处：《烟台大学学报（自然科学与工程版）》2022年第3期269-276,293,共9页Journal of Yantai University(Natural Science and Engineering Edition)

基　　金：国家自然科学基金资助项目(11975195)。

摘　　要：对Λ_(b)→Λτ^(+)τ^(-)中可能存在的新物理效应进行了模型无关的研究。考虑所有可能的算符结构,给出了Λ_(b)→Λτ^(+)τ^(-)过程的螺旋度振幅解析式,对该过程的分支比、轻子对前后不对称性以及纵向极化分数等物理观测量进行计算。发现分支比在10^(-7),且VA算符和SP算符对分支比和轻子前后不对称性的影响较大。若假设新粒子只参与b→sτ^(+)τ^(-)过程,R(Λ_(b))_(τ^(+)τ^(-)/e)对矢量算符比较敏感。现有LHCb实验可对计算结果进行检验,测量结果将有助于寻找新物理效应并为构造新物理模型指明方向。The decay Λ_(b)→Λτ^(+)τ^(-)which is induced by b→sτ^(+)τ^(-) process in a model-independence approach is studied. Including all possible operators, we study the helicity amplitude of Λ_(b)→Λτ^(+)τ^(-), and calculate the branching fraction, the forward-backward asymmetry of lepton pairs and the longitudinal polarization fraction of the process. It is found that the branching fraction is at the order of 10;, which is available in the current LHCb experiment. We also find the VA operators and SP operators could affect remarkably branching fraction and lepton forward-backward asymmetry. If the new operators appear only in b→sτ^(+)τ^(-)process, the ratio R(Λ_(b))_(τ^(+)τ^(-)/e) is very sensitive to vector operators. Our results can be test in the current LHCb experiment, and the comparison between our results and experimental results is helpful for searching for new physics and testing new physical models.

关 键 词：重子 半轻衰变 新物理 轻子味普适性 

分 类 号：O572.241[理学—粒子物理与原子核物理]