Nonperturbative parton distributions and the proton spin problem

TL;DR

This paper uses Lorentz-boosted wave functions to calculate nonperturbative valence parton distributions in hadrons, linking excited multigluon states to the proton spin problem, and provides a model consistent with experimental data.

Contribution

It introduces a simple model for excited multigluon baryon states to explain nonperturbative parton densities and addresses the proton spin problem.

Findings

Valence parton distributions are calculated using boosted static wave functions.

Nonperturbative densities are attributed to excited multigluon states.

The model predicts a proton spin contribution of approximately 0.18 at Q^2=10 GeV^2.

Abstract

The Lorentz contracted form of the static wave functions is used to calculate the valence parton distributions for mesons and baryons, boosting the rest frame solutions of the path integral Hamiltonian. It is argued that nonperturbative parton densities are due to excited multigluon baryon states. A simple model is proposed for these states ensuring realistic behavior of valence and sea quarks and gluon parton densities at $Q^2= 10 (GeV/c)^2$. Applying the same model to the proton spin problem one obtains $\Sigma_3 = 0.18 $ for the same $Q^2$.