Perspective on polarised parton distribution functions and proton spin

Proton spin structure and quark-parton model

The alternative to the standard formulation of the quark-parton model is proposed. Our approach is based on the solution of the master equations relating the structure and distribution functions, which consistently takes into account the intrinsic quark motion in contradistinction to the standard infinite momentum approach, in which this motion is latently suppressed. The model well reproduces ...

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...

Nuclear Parton Distribution Functions

We study nuclear e ects of charged current deep inelastic neutrino-iron scattering in the framework of a χ analysis of parton distribution functions (PDFs). We extract a set of iron PDFs which are used to compute xBj-dependent and Q -dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear c...

Proton spin structure from measurable parton distributions.

We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely polarized proton, we derive a polarization sum rule from the leading generalized parton distributions appearing in hard exclusive processes. For a longitudinally polarized proton, we obtain a helicity decomposition from well-known quark and gluon helicity distributions and ...