论文标题
单线操作员对四个循环的重态度
Renormalisation of singlet operators to four loops
论文作者
论文摘要
在QCD中，Twist 2的规范不变运算符的异常尺寸起关键作用，因为它们控制了Parton分布函数的规模依赖性。值得注意的是，诸如与Gluon分布相关的风味单线操作员与一组非物理操作员（也称为外星人）混合在一起。缺少这种效果会导致两环异常维度的错误结果。 Gluonic运算符的正确重质量化是朝着计算风味单线分布尺度演变的重要一步，现在需要4个循环。利用背景字段方法和增强的BRST对称性，我们为任意质量维度构建了最多4个循环的幽灵和外星操作员基础。此外，对于质量约束4和6的物理操作员，我们在4个回路中提取异常尺寸，对于质量差异8的3个环。
In QCD the anomalous dimensions of gauge invariant operators of twist 2 play a key role, because they control the scale dependence of the parton distribution functions. Notably, the flavour singlet operators, such as those associated to the gluon distribution, mix under renormalisation with a set of unphysical operators, also known as aliens. Missing this effect leads to wrong results already for the two-loop anomalous dimensions. The correct renormalisation of gluonic operators is an important step towards the computation of the scale evolution of flavour singlet parton distributions, which is now required to 4 loops. Leveraging both the background field method and an enhanced BRST symmetry, we construct the required ghost and alien operator basis up to 4 loops for arbitrary mass dimensions. Furthermore, we extract anomalous dimensions at 4 loops, for the physical operators of mass-dimension 4 and 6, and at 3 loops for mass-dimension 8.
