The three-loop splitting functions in QCD: The helicity-dependent case
The three-loop splitting functions in QCD: The helicity-dependent case
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QCD 中的三环分裂函数：螺旋度相关的情况
DOI：
10.1016/j.nuclphysb.2014.10.016
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发表时间：
2014
影响因子：
2.8
通讯作者：
Moch S
中科院分区：
文献类型：
--
作者：
Moch S
我们给出了微扰QCD中强子纵向极化部分子密度演化的主要分裂函数的次次领先级（NNLO）贡献。将我们以前的全Mellin-N计算推广到电磁深度非弹性散射（DIS）中的结构函数g1，得到了夸克-夸克和胶子-夸克分裂函数.它们的夸克-胶子和胶子-胶子对应物是利用引力交换DIS中结构函数的三阶固定N计算、与非极化情况的关系以及丢番图方程组的数学工具导出的。在小动量分数x的区域外，分裂函数的NNLO修正很小，在那里它们表现出很大的双对数增强，但是对部分子密度演化的修正可以在至少x <$10 − 4的范围内是没有问题的。
We present the next-to-next-to-leading order (NNLO) contributions to the main splitting functions for the evolution of longitudinally polarized parton densities of hadrons in perturbative QCD. The quark–quark and gluon–quark splitting functions have been obtained by extending our previous all Mellin-N calculations to the structure function g 1 in electromagnetic deep-inelastic scattering (DIS). Their quark–gluon and gluon–gluon counterparts have been derived using third-order fixed-N calculations of structure functions in graviton-exchange DIS, relations to the unpolarized case and mathematical tools for systems of Diophantine equations. The NNLO corrections to the splitting functions are small outside the region of small momentum fractions x where they exhibit a large double-logarithmic enhancement, yet the corrections to the evolution of the parton densities can be unproblematic down to at least x≈ 10− 4.