arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.00344hep-phhep-ex
收藏

$Υ$和$B$介子衰变中的额外规范玻色子和轻子味普适性破坏

Extra gauge bosons and lepton flavor universality violation in $Υ$ and $B$ meson decays

Cristian H. García-Duque, J. H. Muñoz, Néstor Quintero, Eduardo Rojas

摘要:

轻子味普适性可以通过半轻子$B$介子衰变和轻子$Υ$介子衰变的比值来检验,其中$Υ\equiv Υ(nS)$($n=1,2,3$)。对于带电电流跃迁$b \to cτ\barν_τ$,近年来,不同的风味设施,如BABAR,Belle和LHCb,已经观察到实验和标准模型(SM)之间的差异。而对于中性流跃迁$b \bar{b} \to τ\barτ$,BABAR实验最近报道了一个新的轻子衰变比$R_{Υ(3S)} = {\rm BR}(Υ(3S) \to τ^+τ^-)/{\rm BR}(Υ(3S) \to μ^+μ^-)$的测量结果,在$1.8 σ$水平上与SM的测量结果一致。鉴于这一新的BABAR结果,并考虑到新的物理(NP)解释之间的联系,带电电流$b \to c τ\barν_τ$异常和中性电流$b \bar{b} \to τ\barτ$过程,在这项研究中,我们重新审视NP的后果,这种测量在一个简化的模型与额外的质量规范玻色子,主要耦合到左手轻子的第三代。我们发现,BABAR测量$R_{Υ(3S)}$不能很容易地容纳(在其实验$1σ$范围内)与其他$b \to cτ\barν_τ$数据,暗示对一个新的异常观察。

英文摘要:

Lepton flavor universality can be tested through the ratio of semileptonic $B$ meson decays and leptonic $Υ$ meson decays, with $Υ\equiv Υ(nS)$ ($n=1,2,3$). For the charged-current transitions $b \to cτ\barν_τ$, discrepancies between the experiment and the Standard Model (SM) have been observed in recent years by different flavor facilities such as BABAR, Belle, and LHCb. While for the neutral-current transitions $b \bar{b} \to τ\barτ$, the BABAR experiment reported recently a new measurement of leptonic decay ratio $R_{Υ(3S)} = {\rm BR}(Υ(3S) \to τ^+τ^-)/{\rm BR}(Υ(3S) \to μ^+μ^-)$, showing an agreement with the SM at the $1.8 σ$ level. In light of this new BABAR result and regarding the connection between new physics (NP) interpretations to the charged-current $b \to c τ\barν_τ$ anomalies and neutral-current $b \bar{b} \to τ\barτ$ processes, in this study, we revisit the NP consequences of this measurement within a simplified model with extra massive gauge bosons that coupled predominantly to left-handed leptons of the third-generation. We show that the BABAR measurement of $R_{Υ(3S)}$ cannot easily be accommodated (within its experimental $1σ$ range) together with the other $b \to cτ\barν_τ$ data, hinting toward a new anomalous observable.

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。

↑