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arXiv 1102.3917hep-phhep-exhep-lat
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CKM研究对新物理学的启示

Lessons for new physics from CKM studies

Jack Laiho, Enrico Lunghi, Ruth Van De Water

摘要:

我们使用最新的实验和理论约束对CKM么正三角形进行全局拟合。我们提出了三种不同的约束条件的结果:CKMfitter和UTFit使用的标准输入,标准输入减去|Vub|,标准输入减去|Vub|和|Vcb|。对于所需的非微扰弱矩阵元,我们使用来自www.latticeaverages.org的三味格点量子色动力学平均值;这些平均值已经更新以反映“2010年底”的所有可用格点计算。考虑到目前的理论和实验输入,我们观察到CKM幺正三角形中的约3σ张力,这可以被解释为超出风味部门标准模型的物理学迹象。使用新物理效应的模型无关参数化,我们测试了新物理在K介子混合、B混合或B \rightarrow τ ν衰变中与当前数据的兼容性。虽然每种假设都能适应这种紧张关系,但强烈倾向于B-混合或(在较小程度上)B \rightarrow τ ν衰变中具有新物理的方案。最后,我们用对ΔS = 2和ΔB = 2四费米子算符的贡献来解释这些结果.我们发现,新物理学(与标准模型一样的耦合)的首选尺度是在几百GeV的范围。

英文摘要:

We perform a global fit to the CKM unitarity triangle using the latest experimental and theoretical constraints. We present results for three different sets of constraints: the standard inputs used by CKMfitter and UTFit, the standard inputs minus |Vub|, and the standard inputs minus both |Vub| and |Vcb|. For the required nonperturbative weak matrix elements, we use three-flavor lattice QCD averages from www.latticeaverages.org; these have been updated to reflect all available lattice calculations as of the "End of 2010". Given current theoretical and experimental inputs, we observe an approximately 3σ tension in the CKM unitarity triangle that can be interpreted as sign of physics beyond the standard model in the flavor sector. Using a model-independent parameterization of new physics effects, we test the compatibility of new physics in kaon mixing, in B-mixing, or in B \rightarrow τ ν decay with the current data. Although the tension could be accommodated with each hypothesis, the scenarios with new physics in B-mixing or, to a lesser extent, in B \rightarrow τ ν decay are strongly preferred. Finally, we interpret these results in terms contributions to ΔS = 2 and ΔB = 2 four-fermion operators. We find that the preferred scale of new physics (with Standard Model like couplings) is in the few hundred GeV range.

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