论文标题
用三个$ s_2 $ leptoquark Generations解释Lepton风味普遍性的提示
Explaining the hints for lepton flavour universality violation with three $S_2$ leptoquark generations
论文作者
论文摘要
Leptoquarks是解释Lepton风味普遍性的有趣提示的主要候选人。 In particular, the $SU(2)_L$ doublet of scalar leptoquarks $S_2$ is capable of providing an explanation for the tensions between the measurements and the Standard Model predictions in $(g-2)_μ$, $b\to s\ell^+ \ell^-$ and $b\to cτν$ processes, as well as in non-resonant di-electron production.但是，在最小的设置中，单一的Leptoquark一代，对所有这些问题的共同解释是不可能的，因为这将导致不可接受的大型充电Lepton侵犯侵犯。因此，我们提出了一个具有三代$ s_2 $的模型，每个模型专门与单个Lepton风味，\ textit {i.e.}〜一个模型，将标准模型粒子含量通过ElectroQuark，Muoquark和Tauquark扩展。我们表明，在考虑了其他约束之后，例如源自Electroweak Precision可观测值的限制和$ΔF= 2 $过程后，可以为所有这些违反Lepton风味普遍性的提示提供一个组合的解释。此外，我们发现Tauquark的存在可以通过外壳光子企鹅图生成尺寸六$ {\ cal o} _9^u $ operator，该图与Muquark贡献一起进一步改善了全局拟合到$ b \ to $ b \ for $ b \ ell^ell^+ \ ell^+ \ ell^ell^ell^ - $数据。
Leptoquarks are prime candidates for explaining the intriguing hints for lepton flavour universality violation. In particular, the $SU(2)_L$ doublet of scalar leptoquarks $S_2$ is capable of providing an explanation for the tensions between the measurements and the Standard Model predictions in $(g-2)_μ$, $b\to s\ell^+ \ell^-$ and $b\to cτν$ processes, as well as in non-resonant di-electron production. However, in the minimal setup with a single leptoquark generation, a common explanation for all these issues is not possible as this would lead to unacceptably large charged lepton flavour violation. We therefore propose a model with three generations of $S_2$, each coupling exclusively to a single lepton flavour, \textit{i.e.}~a model extending the Standard Model particle content by an electroquark, a muoquark and a tauquark. We show that after taking into account other constraints, such as those originating from electroweak precision observables and $ΔF=2$ processes, it is possible to provide a combined explanation for all these hints of lepton flavour universality violation. Moreover, we find that the presence of the tauquark can generate a dimension-six ${\cal O}_9^U$ operator via off-shell photon penguin diagrams, which, together with the muoquark contribution, further improves the global fit to $b \to s \ell^+ \ell^-$ data.
