6533b7d2fe1ef96bd125e0e5
RESEARCH PRODUCT
A quark model analysis of Orbital Angular Momentum
Vicente VentoSergio Scopettasubject
PhysicsQuarkNuclear and High Energy PhysicsParticle physicsHigh Energy Physics::LatticeQuark modelHigh Energy Physics::PhenomenologyNuclear TheoryPerturbative QCDFOS: Physical sciencesFísicaPartonGluonHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)Quark–gluon plasmaHigh Energy Physics::ExperimentNucleonNuclear ExperimentSpin-½description
Orbital Angular Momentum (OAM) twist-two parton distributions are studied. At the low energy, hadronic, scale we calculate them for the relativistic MIT bag model and for non-relativistic potential quark models. We reach the scale of the data by leading order evolution using the OPE and 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 $Q^2$. As expected by general arguments, we obtain, that the large gluon OAM contribution is almost cancelled by the gluon spin contribution.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1999-01-15 |