NLO prescription for unintegrated parton distributions

TL;DR

This paper presents a method to generate unintegrated parton distributions at NLO accuracy from known integrated distributions, emphasizing the importance of correct kinematic treatment for consistency.

Contribution

It introduces a prescription for deriving unintegrated parton distributions at NLO using existing integrated distributions and highlights the significance of proper kinematic choices.

Findings

Sufficient accuracy achieved with LO splitting functions and NLO integrated densities

Maintaining correct kinematics by using virtuality scale is crucial

Numerical examples demonstrate the method's effectiveness

Abstract

We show how parton distributions unintegrated over the parton transverse momentum, k_t, may be generated, at NLO accuracy, from the known integrated (DGLAP-evolved) parton densities determined from global data analyses. A few numerical examples are given, which demonstrate that sufficient accuracy is obtained by keeping only the LO splitting functions together with the NLO integrated parton densities. However, it is important to keep the precise kinematics of the process, by taking the scale to be the virtuality rather than the transverse momentum, in order to be consistent with the calculation of the NLO splitting functions.