Results and techniques for higher order calculations within the gradient-flow formalism
Results and techniques for higher order calculations within the gradient-flow formalism
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DOI：
10.1007/jhep06(2019)121
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发表时间：
2019-06-24
影响因子：
5.4
通讯作者：
Prausa, Mario
中科院分区：
文献类型：
--
作者：
Artz, Johannes;Harlander, Robert V.;Prausa, Mario
我们详细描述了 QCD 梯度流形式中可观测量的系统扰动方法的实现。这包括五维场论的所有相关费曼规则和本文考虑的复合算子的集合。标准微扰计算的工具用于获得微扰理论中高阶有限流时间 t 处的格林函数。有限 t 夸克凝聚体的三环结果以及环夸克场到 MSscheme 的转换因子作为应用给出。我们还重新评估了三环胶子凝聚体的早期结果，提高了其准确性。
We describe in detail the implementation of a systematic perturbative approach to observables in the QCD gradient-flow formalism. This includes a collection of all relevant Feynman rules of the five-dimensional field theory and the composite operators considered in this paper. Tools from standard perturbative calculations are used to obtain Green's functions at finite flow time t at higher orders in perturbation theory. The three-loop results for the quark condensate at finite t and the conversion factor for the ringed quark fields to the MSscheme are presented as applications. We also re-evaluate an earlier result for the three-loop gluon condensate, improving on its accuracy.