Four-loop splitting functions in QCD - The gluon-to-quark case
Four-loop splitting functions in QCD - The gluon-to-quark case
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QCD 中的四环分裂函数 - 胶子到夸克的情况
DOI：
10.1016/j.physletb.2023.138215
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发表时间：
2023
影响因子：
4.4
通讯作者：
Falcioni G
中科院分区：
文献类型：
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作者：
Falcioni G
通过对离壳算子矩阵元素的重整化，计算了四阶微扰QCD上胶子-夸克分裂函数pqg的偶N矩N≤20。我们的结果，对一般规范群的解析推导，与迄今为止对该函数获得的所有结果一致，特别是通过物理截面获得的最低五个矩。使用我们的新矩和所有可用的端点约束，我们构建了四环pqg (x)的近似值，它应该足以用于广泛的对撞机物理应用。由这些和相应的夸克-夸克分裂函数引起的n3lo修正导致单重夸克分布尺度导数的微扰精度显著提高，在α s= 0.2的标准参考尺度下，在x≥10−4时的影响小于1%。
We have computed the even-N moments N≤ 20 of the gluon-to-quark splitting function P qg at the fourth order of perturbative QCD via the renormalization of off-shell operator matrix elements. Our results, derived analytically for a general gauge group, agree with all results obtained for this function so far, in particular with the lowest five moments obtained via physical cross sections. Using our new moments and all available endpoint constraints, we construct approximations for the four-loop P qg (x) that should be sufficient for a wide range of collider-physics applications. The N 3 LO corrections resulting from these and the corresponding quark-quark splitting functions lead to a marked improvement of the perturbative accuracy for the scale derivative of the singlet quark distribution, with effects of 1% or less at x≳ 10− 4 at a standard reference scale with α s= 0.2.