In this talk, I review the merit of introducing and measuring the quark orbital angular momentum contribution to the spin of the nucleon in the context of quantum chromodynamics.
We describe a new type of models for nucleon generalized parton distributions (GPDs) H and E. They are heavily based on the fact nucleon GPDs require to use two forms of double distribution (DD) representations. The outcome of the new treatment is that the usual "DD+D-term" construction should be amended by an extra term, [Formula: see text] which has the DD structure α/βe(β, α), with e(β, α) being the DD that generates GPD E(x, ξ). We found that this function, unlike the D-term, has support in the whole -1 ≤ x ≤ 1 region. Furthermore, it does not vanish at the border points |x| = ξ.
Quark spin and orbital angular momentum from proton generalized parton distributions
