Experimental consistency in parton distribution fitting

Parton Distribution Functions and QCD Global Fitting

High energy hadrons interact through their quark and gluon constituents. The interactions become weak at short distances thanks to the asymptotic freedom property of QCD, which allows perturbation theory to be applied to a rich variety of experiments. The nonperturbative nature of the proton for single hard interactions is thus characterized by Parton Distribution Functions (PDFs) fa(Q, x) of m...

Parton distribution functions in nuclei

Optimum nuclear parton distributions are determined by an analysis of muon and electron deep inelastic scattering data. Assuming simple A dependence and polynomial functions of x and 1−x for nuclear modification of parton distributions, we determine the initial distributions by a χ 2 analysis. Although valence-quark distributions are relatively well determined except for the small-x region, ant...

Parton Distribution Functions

Dynamical parton distribution functions

Recent measurements for F2(x, Q ) have been analyzed in terms of the ‘dynamical’ and ‘standard’ parton model approach at NLO and NNLO of perturbative QCD. Having fixed the relevant NLO and NNLO parton distributions, the implications and predictions for the longitudinal structure function FL(x,Q ) are presented. It is shown that the previously noted extreme perturbative NNLO/NLO instability of F...

Parton Distributions : Experimental aspects