A Perturbative QCD Based Study of Polarized Nucleon Structure in the Transition Region and Beyond: "Quarks, Color Neutral Clusters, and Hadrons"

A large fraction of the world data on both polarized and unpolarized inclusive $ep$ scattering at large Bjorken $x$ lies in the resonance region where a correspondence with the deep inelastic regime, known as Bloom and Gilman's duality, was observed. Recent analyses of the $Q^2$ dependence of the data show that parton-hadron duality is inconsistent with the twist expansion at low values of the final state invariant mass. We investigate the nature of this disagreement, and we interpret its occurrence in terms of contributions from non partonic degrees of freedom in a preconfinement model.