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arXiv 1507.07567hep-phhep-ex
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一个微扰的轻子特有的双希格斯偶线模型面临着超越标准模型的物理学实验线索

A perturbed lepton-specific two-Higgs-doublet model facing experimental hints for physics beyond the Standard Model

Andreas Crivellin, Julian Heeck, Peter Stoffer

摘要:

BaBar、Belle和LHCb的合作报告了$B\to Dτν$和$B\to D^*τν$中大约$3.8σ$的新物理的证据。在μ子的异常磁矩中也存在约$3σ$的长期持续的差异,并且$τ\toμνν$的分支比为$1.8σ$($2.4σ$),高于使用HFAG(PDG)值的标准模型期望。此外,CMS发现了$h\toμτ$非零衰减率的暗示。有趣的是,所有这些观察都可以通过引入新的标量来解释。在这篇文章中,我们考虑这些过程中的轻子特定的两个希格斯偶极子模型(即X型)与额外的非标准汤川耦合。研究发现,可以用修改的Higgs-$τ$耦合来容纳$τ\toμνν$。μ子的反常磁矩可以解释,如果额外的中性CP-偶希格斯$H$是轻的(低于100 GeV)。另外,$R(D)$和$R(D^*)$可以很容易地用额外的$t$ - $c$ -希格斯耦合来解释。将这些$t$-$c$耦合与轻$H$结合,$t\to H c$的衰变率可以在LHC的可测试范围内。$h\toμτ$中的效应也是可能的,但在这种情况下,由于不可避免的$τ\toμγ$衰变,很难同时解释μ子的异常磁矩。

英文摘要:

The BaBar, Belle, and LHCb collaborations have reported evidence for new physics in $B\to Dτν$ and $B\to D^*τν$ of approximately $3.8σ$. There is also the long lasting discrepancy of about $3σ$ in the anomalous magnetic moment of the muon, and the branching ratio for $τ\toμνν$ is $1.8σ$ ($2.4σ$) above the Standard Model expectation using the HFAG (PDG) values. Furthermore, CMS found hints for a non-zero decay rate of $h\toμτ$. Interestingly, all these observations can be explained by introducing new scalars. In this article we consider these processes within a lepton-specific two-Higgs doublet model (i.e. of type X) with additional non-standard Yukawa couplings. It is found that one can accommodate $τ\toμνν$ with modified Higgs--$τ$ couplings. The anomalous magnetic moment of the muon can be explained if the additional neutral CP-even Higgs $H$ is light (below 100 GeV). Also $R(D)$ and $R(D^*)$ can be easily explained by additional $t$--$c$--Higgs couplings. Combining these $t$--$c$ couplings with a light $H$ the decay rate for $t\to H c$ can be in a testable range for the LHC. Effects in $h\toμτ$ are also possible, but in this case a simultaneous explanation of the anomalous magnetic moment of the muon is difficult due to the unavoidable $τ\toμγ$ decay.

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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