Speaker
Description
We developed a non-perturbative model for valence parton distribution functions (PDFs) based on the mean field interactions of valence quarks in the nucleonic interior. The model is based on the separation of the valence three-quark cluster and residual system in the nucleon. Then the nucleon structure function is calculated within the effective light-front diagrammatic approach introducing nonperturbative light-front valence quark and residual system wave functions. Based on the model one obtained a new relation between the position of the peak of $xq_V(x)$ distribution of the valence quark and the effective mass of the residual system, $m_R$: $x_{peak} \approx {1\over 4} (1-{m_R\over m_N})$ at starting $Q^2$ and explain the difference in the peak positions for d- and u- quarks to be due to an expected larger residual mass in the case of valence d- quark distribution. The parameters of the model are fixed by fitting the calculated valence quark distributions to the phenomenological PDFs. This allowed us to estimate the overall mean field contribution in baryonic and momentum sum rules. The evaluated parameters of the non-perturbative wave functions of valence 3q- and residual system can be used in calculation of other observables such as nucleon form factors, generalized partonic and transverse momentum distributions.