6533b820fe1ef96bd1279b4d
RESEARCH PRODUCT
The gluon spin in the chiral bag model
Hee-jung LeeMannque RhoDong-pil MinByung-yoon ParkVicente Ventosubject
PhysicsQuarkNuclear and High Energy PhysicsParticle physicsNuclear TheorySpin polarizationHigh Energy Physics::LatticeNuclear TheoryHigh Energy Physics::PhenomenologyQuark modelFOS: Physical sciencesFísicaExpectation valueGluonNuclear Theory (nucl-th)RenormalizationHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)Proton spin crisisBoundary value problemdescription
We study the gluon polarization contribution at the quark model renormalization scale to the proton spin, $\Gamma$, in the chiral bag model. It is evaluated by taking the expectation value of the forward matrix element of a local gluon operator in the axial gauge $A^+=0$. It is shown that the confining boundary condition for the color electric field plays an important role. When a solution satisfying the boundary condition for the color electric field, which is not the conventionally used but which we favor, is used, the $\Gamma$ has a positive value for {\it all} bag radii and its magnitude is comparable to the quark spin polarization. This results in a significant reduction in the relative fraction of the proton spin carried by the quark spin, which is consistent with the small flavor singlet axial current measured in the EMC experiments.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2000-01-01 | Physics Letters B |