摘要
研究了在低能情况下标准模型中的和有效场理论描述的保持l,l′质量的依赖性的弱电流过程,包括极化的和非极化的L,L→ll′l′_(νlνL)衰变.澄清了之前标准模型关于衰变率的两个计算的差异并提高了计算精度.最近在τ→eγ珔vevτ过程中发现的3.5σ反常可以通过我们对第一代B工厂已有数据分析测量的τ→eee珔veντ衰变过程的精确预测来检验.它揭示了如何通过对di-l′质量分布(使用合适的截断条件)和非对称T矩阵的测量显示出关联的末态无中微子轻子味破缺过程.
The L→ll′l′_(νlνL) decays(L=τ,μ;l,l′=μ,e)in the Standard Model(SM)and in the effective field theory(EFT)description of the weak charged current are studied at low energy,both for polarized and unpolarized L,keeping for the first time l,l′ mass dependence.The discrepancy is clarified between two previous SM calculations improving their precision.The recent 3.5σ anomaly found inτ→eγ νeντcould be checked using our precise prediction for theτ→eeeνeντ decays,which shall be measured analysing already existing data from the first generation B-factories.It is shown how measurements of the di-l′ mass distribution(with appropriate cuts)and T-asymmetries are able to reveal the corresponding lepton flavor violating(LFV)processes without neutrinos in the final state.
基金
Supported by Conacyt,México
关键词
μ衰变
τ衰变
轻子相互作用
Michel参数
T破缺
轻子味破缺
decays of muons
decays of taus
leptonic interactions
Michel parameters
T-violation
lepton flavor violation
