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arXiv 1204.0791hep-phhep-exhep-lat
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LHC时代的风味物理学:晶格的作用

Flavor Physics in the LHC era: the role of the lattice

Jack Laiho, Enrico Lunghi, Ruth S. Van de Water

摘要:

我们讨论了目前的现状,全球适合CKM酉三角形使用最新的实验和理论约束。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;这些平均值已从参考文献[1]更新,以反映截至“2011年底”的所有可用格点计算。由于大于3西格玛之间的分歧提取|Vub|从包容性和排他性的半轻子b -> u l nu(l = e,mu)衰变,特别强调的是一个干净的适合,我们从这些衰变中删除的信息。考虑到目前的理论和实验输入,我们观察到CKM幺正三角形中大约3 σ的张力,这可能表明夸克风味部门中存在新的物理学。使用模型独立的参数化的新物理效应,我们测试的兼容性的数据与场景中,新的物理是在K介子混合,在B-混合,或在B -> τ nu衰变。我们发现,在B -> τ nu衰变或B-混合中具有新物理的场景大致同样优选。最后,我们解释了这些结果的贡献德尔塔S = 2和德尔塔B = 2四费米子运营商。我们发现,新物理学的首选尺度(与标准模型一样的耦合)是在几百GeV的范围内。

英文摘要:

We discuss the present status of global fits to the CKM unitary triangle using the latest experimental and theoretical constraints. For the required nonperturbative weak matrix elements, we use three-flavor lattice QCD averages from www.latticeaverages.org; these have been updated from Ref. [1] to reflect all available lattice calculations as of the "End of 2011". Because of the greater than 3 sigma disagreement between the extraction of |Vub| from inclusive and exclusive semileptonic b -> u l nu (l = e,mu) decays, particular emphasis is given to a clean fit in which we remove the information from these decays. Given current theoretical and experimental inputs, we observe an approximately 3 sigma tension in the CKM unitarity triangle that may indicate the presence of new physics in the quark-flavor sector. Using a model-independent parameterization of new-physics effects, we test the compatibility of the data with scenarios in which the new physics is in kaon mixing, in B-mixing, or in B -> tau nu decay. We find that scenarios with new physics in B -> tau nu decay or in B-mixing are approximately equally preferred. Finally, we interpret these results in terms contributions to Delta S = 2 and Delta B = 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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