Dynamical next-to-next-to-leading order parton distributions and the perturbative stability of F_L(x,Q^2)

Abstract

It is shown that the previously noted extreme perturbative instability of the longitudinal structure function F_L(x,Q^2) in the small Bjorken-$x$ region, is a mere artefact of the commonly utilized `standard' gluon distributions. In particular it is demonstrated that using the appropriate -- dynamically generated -- parton distributions at NLO and NNLO, F_L(x,Q^2) turns out to be perturbatively rather stable already for Q^2 $\ge$ O(2-3 GeV^2).

Comments: 4 pages, 3 figures, 1 table, to appear in the proceedings of 14th International QCD Conference (QCD08), Montpellier, France, 7-12 July 2008