Unintegrated parton distributions and correlation functions

TL;DR

This paper highlights the limitations of collinear factorization in describing exclusive final states in high-energy processes and advocates for using fully unintegrated parton correlation functions with gauge-invariant definitions.

Contribution

It introduces gauge-invariant definitions of unintegrated parton correlation functions and establishes a factorization theorem for one jet production in deep inelastic scattering.

Findings

Standard collinear approach is insufficient for exclusive states

Fully unintegrated correlation functions are necessary for proper descriptions

Factorization theorem for one jet production is formulated

Abstract

We discuss the limitations of the standard collinear approach. The kinematical approximations necessary to derive the collinear factorization are insufficient for the description of the exclusive final states. We argue that for a proper treatment of the final states one needs to use fully unintegrated parton correlation functions. We introduce the gauge invariant definitions of these objects and the factorization theorem for one jet production in deep inelastic scattering.