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arXiv 0810.4918hep-ph
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电弱标准模型之外的轻子π介子衰变和物理

Leptonic Pion Decay And Physics Beyond The Electroweak Standard Model

Bruce A. Campbell, Ahmed Ismail

摘要:

轻子介子衰变$R_π \equiv (Γ(π^- \to e ν_e))/(Γ(π^- \to μν_μ))$中的分支比是电弱标准模型之外新相互作用的一个强灵敏的探针。这是由于衰减的标准模型振幅的手征性抑制,这导致对比率的精确预测,以及新贡献的抑制振幅干扰。我们计算,包括QCD修正,$R_π$的贡献产生于广泛的选择标准模型扩展,它是敏感的,包括:超对称理论、光理论中违反R宇称的相互作用(电弱尺度)轻子自由度、额外双重希格斯玻色子的非极小模型、夸克和轻子在有和没有超对称性的情况下复合的模型,和具有强TeV尺度引力相互作用的模型。与现有的测量相比,$R_π$,我们提供了这些类的模型的限制,我们的计算也代表了最先进的理论基准,对即将到来的一轮轻子介子衰变实验的结果进行比较。

英文摘要:

The ratio of branching ratios in leptonic pion decay $R_π \equiv (Γ(π^- \to e ν_e))/(Γ(π^- \to μν_μ))$ is a powerfully sensitive probe of new interactions beyond the electroweak standard model. This is due to the chirality suppression of the standard model amplitude for the decay, which results in a precise prediction for the ratio, and suppressed amplitudes for new contributions to interfere with. We calculate, including QCD corrections, the contributions to $R_π$ arising from a broad selection of standard model extensions to which it is sensitive, including: R-parity violating interactions in supersymmetric theories, theories with light (electroweak scale) leptoquark degrees of freedom, non-minimal models of extra doublet Higgs bosons, models in which the quarks and leptons are composite both with and without supersymmetry, and models with strong TeV scale gravitational interactions. Comparing with existing measurements of $R_π$ we provide limits on each of these classes of models; our calculations also represent state of the art theoretical benchmarks against which the results from the upcoming round of leptonic pion decay experiments may be compared.

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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