On quartic colour factors in splitting functions and the gluon cusp anomalous dimension
On quartic colour factors in splitting functions and the gluon cusp anomalous dimension
复制标题
DOI：
10.1016/j.physletb.2018.06.017
复制
发表时间：
2018-05
影响因子：
4.4
通讯作者：
S. Moch;B. Ruijl;Takahiro Ueda;J. Vermaseren;A. Vogt
中科院分区：
文献类型：
--
作者：
S. Moch;B. Ruijl;Takahiro Ueda;J. Vermaseren;A. Vogt
我们计算了四次卡西米尔不变量对N≤16的扭转-2自旋-N算子的四环异常维的贡献。这些结果为部分子分布演化的次-次-次-次-前阶（n3lo）分裂函数pik (3)(x)的结构提供了新的信息，并促进了包含四次卡西米尔贡献的（光）胶子尖异常维数的近似表达式。通过对低阶“卡西米尔尺度”的推广，这些量被证明与相应的夸克结果密切相关。利用这些发现，我们给出了QCD中四环胶子尖异常维的近似结果，足以用于现象学应用。
We have computed the contributions of the quartic Casimir invariants to the four-loop anomalous dimensions of twist-2 spin-N operators at N≤ 16. The results provide new information on the structure of the next-to-next-to-next-to-leading order (N 3 LO) splitting functions P ik (3)(x) for the evolution of parton distributions, and facilitate approximate expressions which include the quartic-Casimir contributions to the (light-like) gluon cusp anomalous dimension. These quantities turn out to be closely related, by a generalization of the lower-order ‘Casimir scaling’, to the corresponding quark results. Using these findings, we present an approximate result for the four-loop gluon cusp anomalous dimension in QCD which is sufficient for phenomenological applications.