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arXiv 2109.07490hep-ph
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在汤川耦合和味对称中寻找BSM物理

Searching for BSM Physics in Yukawa Couplings and Flavour Symmetries

J. Alonso-Gonzalez, A. de Giorgi, L. Merlo, S. Pokorski

备注：
34 pages, 13 tables, 4 figures. Version accepted for publication on JHEP: references added, typos corrected, results unchanged
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摘要：

在标准模型有效场论的框架下，我们比较了可能对$f\bar{f}h$有效耦合有贡献的新物理尺度的下界，这些下界是在假设相关dim 6算子的Wilson系数服从某种味结构的情况下，从不同观测量的测量中获得的：无论是最小味违反（MFV）的解释或味对称，经常被用来解释观察到的费米子质量和混合模式。我们执行一个全球性的分析的界限以下的限制在LHC实验的希格斯玻色子玻色子生产和衰变的对角耦合。另一组界限是从限制非对角耦合约束的各种口味变化的中性电流（FCNC）和辐射衰变过程。以目前LHC数据的精确度，FCNC数据在新物理学的尺度上比对撞机数据给出了更强的界限（显然，对于MFV模拟，只有对撞机数据是相关的）：一旦威尔逊系数尊重某些味道结构，所获得的界限就在TeV范围内。在夸克的情况下，这些限制与SM汤川耦合的百分之几的偏差是相容的，并且只比从现有的对撞机数据中获得的限制稍微严格一些。相反，对于轻子，FCNC边界更强，那么在不久的将来对撞机数据中的信号将意味着味道对称性的破坏，或者表明在标准模型之外存在额外的贡献，影响味道观测值，导致取消。

英文摘要：

In the framework of the Standard Model Effective Field Theory, we compare the lower bounds on the scale of new physics possibly contributing to the $f\bar{f}h$ effective couplings, obtained from the measurements of different observables, under the assumption that the Wilson coefficients of the relevant dim 6 operators respect certain flavour structure: either the Minimal Flavour Violation (MFV) ansatz or a flavour symmetry, often invoked to explain the observed pattern of fermion masses and mixings. We perform a global analysis of the bounds following from the limits on the diagonal couplings measured in the Higgs boson production and decays at the LHC experiments. Another set of bounds is obtained from the limits on non-diagonal couplings constrained by the variety of flavour changing neutral current (FCNC) and radiative decay processes. With the present precision of the LHC data, the FCNC data give stronger bounds on the scale of new physics than the collider data (obviously, for the MFV ansatz only collider data are relevant): once the Wilson coefficients respect some flavour structure, the obtained bounds are in the TeV range. In the quark case, these limits are compatible with a few percent deviations from the SM Yukawa couplings and only mildly more stringent than those obtained from the available collider data. For leptons, instead, the FCNC bounds are stronger and then a signal in the near future collider data would mean the violation of the flavour symmetry or indicate the presence of additional beyond the Standard Model contributions, affecting the flavour observables, that leads to cancellations.

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