arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1804.08078hep-phhep-ex
收藏

$R_D$ / $R_{D^*}$难题的解决

Resolution of $R_D$/$R_{D^*}$ puzzle

Ashutosh Kumar Alok, Dinesh Kumar, Suman Kumbhakar, S Uma Sankar

备注：
6 pages, 2 figures (Accepted for publication in Physics Letters B)
发表信息：
Phys. Lett. B784 (2018) 16-20
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

近年来，风味物理学中令人兴奋的结果之一是$R_D$ / $R_{D^*}$之谜。由B工厂实验BaBar和Belle以及LHCb实验进行的这些风味比率的测量与标准模型的预期相差约$4σ$。这些测量结果表明，$b\rightarrow cτ\barν$的衰变机制与$b\rightarrow c(μ/e)\barν$的衰变机制不同。这种荷轻子普适性违反特别有趣，因为这些衰变发生在标准模型中的树水平。特别是，我们预计一个适度大的新的物理贡献$b\rightarrow cτ\barν$。可以解释$R_D$ / $R_{D^*}$之谜的不同类型的新物理振幅先前已经被识别。在这封信中，我们表明$τ$和$D^*$的极化分数和$B\rightarrow D^*τ\barν$衰变中的角不对称性$A_{FB}$和$A_{LT}$有能力唯一地识别新物理的洛伦兹结构。对这四个观测量的测量将导致这样的识别。

英文摘要：

One of the exciting results in flavor physics in recent times is the $R_D$/$R_{D^*}$ puzzle. The measurements of these flavor ratios performed by the B-factory experiments, BaBar and Belle, and the LHCb experiment are about $4σ$ away from the Standard Model expectation. These measurements indicate that the mechanism of $b\rightarrow cτ\barν$ decay is not identical to that of $b\rightarrow c(μ/e)\barν$. This charge lepton universality violation is particularly intriguing because these decays occur at tree level in the Standard Model. In particular, we expect a moderately large new physics contribution to $b\rightarrow cτ\barν$. The different types of new physics amplitudes, which can explain the $R_D$/$R_{D^*}$ puzzle, have been identified previously. In this letter, we show that the polarization fractions of $τ$ and $D^*$ and the angular asymmetries $A_{FB}$ and $A_{LT}$ in $B\rightarrow D^*τ\barν$ decay have the capability to uniquely identify the Lorentz structure of the new physics. A measurement of these four observables will lead to such an identification.

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。

↑