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arXiv 1708.04072hep-ph
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B_c \to τ nu从LEP1分支比的限制及R(D(*))反常的结果

Constraint on the branching ratio of B_c \to tau nu from LEP1 and consequences for R(D(*)) anomaly

A. G. Akeroyd, Chuan-Hung Chen

摘要:

最近,在带有带电标量H^ \pm的模型中,R(D*)和$B_c \to τν$的分支比(BR)之间的相关性引起了人们的兴趣。$H^\pm$单独对R(D*)的任何增强(为了与当前数据一致)也会增强$BR(B_c \to τν$),这在强子对撞机上还没有直接的研究。我们发现,LEP数据采取的Z峰要求BR($B_c \to τν$)<10%,这个约束是显着强于最近的约束BR($B_c \to τν$)< 30%,从考虑寿命的B_c。为了遵守这一新的约束,仅根据$H^\pm$对R(D)和R(D*)异常的任何解释都需要R(D*)的未来测量值更接近标准模型的预测。如果L3协作使用在Z峰处获取的所有数据,则将获得BR($B_c \to τν$)(或其第一次测量)的更强限值。

英文摘要:

Recently there has been interest in the correlation between R(D*) and the branching ratio (BR) of $B_c \to τν$ in models with a charged scalar H^\pm. Any enhancement of R(D*) by $H^\pm$ alone (in order to agree with current data) also enhances $BR(B_c \to τν$), for which there has been no direct search at hadron colliders. We show that LEP data taken at the Z peak requires BR($B_c \to τν$) < 10%, and this constraint is significantly stronger than the recent constraint BR($B_c \to τν$) < 30% from considering the lifetime of B_c. In order to respect this new constraint, any explanation of the R(D) and R(D*) anomaly in terms of $H^\pm$ alone would require the future measurements of R(D*) to be even closer to the Standard Model prediction. A stronger limit on BR($B_c \to τν$) (or its first measurement) would be obtained if the L3 collaboration used all its data taken at the Z peak.

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。

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