Two-body non-leptonic heavy-to-heavy decays at NNLO in QCD factorization
Two-body non-leptonic heavy-to-heavy decays at NNLO in QCD factorization
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QCD 分解中 NNLO 处的二体非轻子重到重衰变
DOI：
10.1007/jhep09(2016)112
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Li Xin-Qiang
中科院分区：
文献类型：
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作者：
Huber Tobias;Kraenkl Susanne;Li Xin-Qiang
在QCD分解的框架下计算了衰变的双圈顶点修正和Λ B→ Λ+ c L−，其中L是来自集合{π，ρ，K（λ），a1}的轻介子.这些衰变是QCD因子分解方法的范例，因为只有颜色允许的树振幅有助于领先的功率。因此，他们是敏感的功率校正的大小，一旦他们的领导权力微扰膨胀是在控制之下。在这里，我们计算的两个回路校正的领先功率硬散射内核，并给出卷积内核几乎完全解析的结果。我们新计算出的贡献相当于树振幅的幅度的正向偏移0.2%。然后，我们进行了广泛的唯象分析NNLO在QCD因子分解，使用最新的非微扰输入参数的值。鉴于NNLO微扰校正和形状因子的更新值增加了分支比的理论预测，而实验中心值同时降低，我们通过适当选择的衰变通道比重新分析了功率校正的作用和潜在大小。
We evaluate in the framework of QCD factorization the two-loop vertex corrections to the decaysand Λ b→ Λ+ c L−, where L is a light meson from the set {π, ρ, K (∗), a 1}. These decays are paradigms of the QCD factorization approach since only the colour-allowed tree amplitude contributes at leading power. Hence they are sensitive to the size of power corrections once their leading-power perturbative expansion is under control. Here we compute the two-loopcorrection to the leading-power hard scattering kernels, and give the results for the convoluted kernels almost completely analytically. Our newly computed contribution amounts to a positive shift of the magnitude of the tree amplitude by∼ 2%. We then perform an extensive phenomenological analysis to NNLO in QCD factorization, using the most recent values for non-perturbative input parameters. Given the fact that the NNLO perturbative correction and updated values for form factors increase the theory prediction for branching ratios, while experimental central values have at the same time decreased, we reanalyze the role and potential size of power corrections by means of appropriately chosen ratios of decay channels.