Leptonic Pion Decay And Physics Beyond The Electroweak Standard Model
Leptonic Pion Decay And Physics Beyond The Electroweak Standard Model
复制标题
轻子π介子衰变和超越电弱标准模型的物理
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
A. Ismail
中科院分区：
文献类型：
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作者：
B. Campbell;A. Ismail
本文研究了轻子π介子衰变$R_{pi} equiv（Gamma（pi^- o e
u_e））/（Gamma（pi^- 吴武
u_mu））$是电弱标准模型之外的新相互作用的强灵敏探针。这是由于衰减的标准模型振幅的手性抑制，这导致对比率的精确预测，以及新贡献的抑制振幅干扰。我们计算了包括QCD修正在内的对R_{pi}的贡献，这些贡献来自于广泛选择的标准模型扩展，这些扩展是敏感的，包括：超对称理论中的r宇称破坏相互作用，（电弱标度）leptoquark自由度，额外的双重希格斯玻色子的非最小模型，夸克和轻子在有和没有超对称性的情况下都是复合的模型，和具有强TeV尺度引力相互作用的模型。与现有的测量$R_{pi}$相比，我们提供了这些类模型的限制，我们的计算也代表了最先进的理论基准，从即将到来的一轮轻子π衰变实验的结果进行比较。
The ratio of branching ratios in leptonic pion decay $R_{pi} equiv (Gamma(pi^- o e
u_e))/(Gamma(pi^- o mu
u_mu))$ 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 $R_{pi}$ 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 $R_{pi}$ 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.