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arXiv 1801.09455hep-lat
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$N_f = 2$ QCD中BSM四夸克算符的非微扰重整化和运行

Non-Perturbative Renormalisation and Running of BSM Four-Quark Operators in $N_f = 2$ QCD

Petros Dimopoulos, Gregorio Herdoíza, Mauro Papinutto, Carlos Pena, David Preti, Anastassios Vladikas

摘要:

我们进行非微扰研究的尺度相关的重整化因子的一套完整的六维四费米子运营商。在双动力学味格点QCD($N_f = 2$)框架下,确定了一种特殊的薛定谔泛函重整化方案在连续极限下的重整化群运行.该理论是正规化的格元威尔逊行动和$\mathcal{O}(a)$-改进的威尔逊费米子。对于其中一个算子,计算已经在参考文献[1]中完成;本工作完成了对其余算子基础的研究,在相同的模拟(组态系综)上。相关的弱矩阵元出现在几个算符乘积展开式中;在$ΔF = 2$跃迁中,它们包含QCD长距离效应,包括来自超标准模型(BSM)过程的贡献。这些运营商的混合下重新正规化和他们的RG运行是由异常的尺寸矩阵。文献[2]中给出了算符基的RG形式,并在非线性光学微扰理论中计算了反常维数矩阵。这里的讨论扩展到矩阵步进缩放函数(矩阵SSFs),这是在有限大小的递归技术中使用。我们依赖于这些矩阵SSF获得非微扰估计的运营商异常尺寸的尺度范围从$\mathcal{O}(Λ_{\rm QCD})$到$\mathcal{O}(M_W)$。

英文摘要:

We perform a non-perturbative study of the scale-dependent renormalisation factors of a complete set of dimension-six four-fermion operators. The renormalisation-group (RG) running is determined in the continuum limit for a specific Schrdinger Functional (SF) renormalisation scheme in the framework of lattice QCD with two dynamical flavours ( $N_f = 2$ ). The theory is regularised on a lattice with a plaquette Wilson action and $\mathcal{O}(a)$-improved Wilson fermions. For one of these operators, the computation had been performed in ref. [1]; the present work completes the study for the rest of the operator basis, on the same simulations (configuration ensembles). The related weak matrix elements arise in several operator product expansions; in $ΔF = 2$ transitions they contain the QCD long-distance effects, including contributions from beyond-Standard Model (BSM) processes. Some of these operators mix under renormalisation and their RG-running is governed by anomalous dimension matrices. In ref. [2] the RG formalism for the operator basis has been worked out in full generality and the anomalous dimension matrix has been calculated in NLO perturbation theory. Here the discussion is extended to the matrix step-scaling functions (matrix-SSFs), which are used in finite-size recursive techniques. We rely on these matrix-SSFs to obtain non-perturbative estimates of the operator anomalous dimensions for scales ranging from $\mathcal{O}(Λ_{\rm QCD})$ to $\mathcal{O}(M_W)$.

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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