Eur. Phys. J. C (2010) 66: 163-172
https://doi.org/10.1140/epjc/s10052-010-1242-5

Regular Article - Theoretical Physics

NLO prescription for unintegrated parton distributions

¹ Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE, UK
² Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, 188300, Russia

^* e-mail: Graeme.Watt@cern.ch

Received: 2 October 2009
Revised: 23 November 2009
Published online: 21 January 2010

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.