Year: 2026
Type: preprint
Abstract: 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 $x_b$.
Source: arXiv (Cornell University)
Author: Guiot, Benjamin
Institution: Universidad Técnica Federico Santa María
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221014331