发表机构
Universidad Técnica Federico Santa María（费德里科·圣玛丽亚理工大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文论证标准CGC缺乏共线部分，将Wilson线重新解释为软因子，通过恢复共线交换得到小-x PDF新定义，并讨论其演化。
AI 中文摘要
我们特别关注不同类型的胶子——共线胶子、软胶子和Glauber胶子，并论证在标准表述中，CGC并不包含与TMD因子化进行有意义比较所需的共线部分。通常被识别为质子矩阵元一部分的CGC Wilson线，应被解释为软因子的等价物。通过恢复缺失的共线交换，我们利用CGC费曼规则对DIS截面进行显式计算，得到了小-$x$ PDF的新定义。所得表达式可以写成类似于TMD因子化的形式，但并不等价于TMD因子化。最后，我们讨论了这些关于快度截断$\Lambda$和Bjorken变量$x_b$的小-$x$ PDF的演化。
英文摘要
Paying particular attention to the different types of gluons, collinear, soft and Glauber, we argue that, in its standard formulation, the CGC does not contain the collinear sector required for a meaningful comparison with TMD factorization. The CGC Wilson lines usually identified as part of the proton matrix element should instead be interpreted as the equivalent of a soft factor. Restoring the missing collinear exchanges, we obtain a new definition of small-$x$ PDFs from an explicit calculation of the DIS cross section using CGC Feynman rules. The resulting expression can be cast in a form resembling TMD factorization without being equivalent to it. Finally, we discuss the evolution of these small-$x$ PDFs with respect to the rapidity cutoff $Λ$ and the Bjorken variable $x_b$.
Comments17 pages, 4 figures
