Understanding the evolution of transverse-momentum dependent parton densities

TL;DR

This paper compares various definitions of transverse-momentum dependent parton distribution functions, analyzing their renormalization properties and advocating for the 'pure light-like' approach and light-cone gauge for better theoretical consistency.

Contribution

It provides a comparative analysis of different TMD PDF definitions focusing on their renormalization-group behavior and introduces arguments supporting the 'pure light-like' and light-cone gauge approaches.

Findings

One-loop anomalous dimensions are calculated and compared.

Arguments favoring the 'pure light-like' definition are presented.

The light-cone gauge is recommended for TMD PDFs.

Abstract

Different approaches to define transverse-momentum dependent parton distribution functions are considered from the point of view of their renormalization-group properties. The associated one-loop anomalous dimensions of these quantities are presented and compared to each other. We give arguments in favor of the "pure light-like" definition, and the use of the light-cone gauge.