6533b821fe1ef96bd127b8fe
RESEARCH PRODUCT
Orbital angular momentum parton distributions in quark models
S. ScopettaV. Ventosubject
polarized DIS; Generalized parton distributions; evolution equationsHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)evolution equationsHigh Energy Physics::PhenomenologyNuclear TheoryPhysics::OpticsFOS: Physical sciencesHigh Energy Physics::ExperimentNuclear ExperimentGeneralized parton distributionspolarized DISdescription
At the low energy, {\sl hadronic}, scale we calculate Orbital Angular Momentum (OAM) twist-two parton distributions for the relativistic MIT bag model and for non-relativistic quark models. We reach the scale of the data by leading order evolution in perturbative QCD. We confirm that the contribution of quarks and gluons OAM to the nucleon spin grows with $Q^2$, and it can be relevant at the experimental scale, even if it is negligible at the hadronic scale, irrespective of the model used. The sign and shape of the quark OAM distribution at high $Q^2$ may depend strongly on the relative size of the OAM and spin distributions at the hadronic scale. Sizeable quark OAM distributions at the hadronic scale, as proposed by several authors, can produce the dominant contribution to the nucleon spin at high $Q^2$.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1999-07-21 |