Polarized Structure Function of Nucleon and Orbital Angular Momentum

Journal Article · Wed Jun 13 04:00:00 EDT 2007 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2750822· OSTI ID:21063961

Arash, Firooz ^[1]; Taghavi-Shahri, Fatemeh ^[2]

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1. Physics Department, Tafresh University, Tafresh (Iran, Islamic Republic of)
2. Physics Department, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

We have utilized the concept of valon model to calculate the spin structure function of a constituent quark. This structure is universal and arises from perturbative dressing of a valence quark in QCD. With a convolution method the polarized structure functions of proton, neutron, and deuteron are obtained. Our results agree rather well with all available experimental data. It suggests that the sea quark contribution to the spin of nucleon is consistent with zero, in agreement with HERMES data. It also reveals that while the total quark contribution to the spin of a constituent quark, or valon, is almost constant and equal to one, the gluon contribution grows with the increase of Q2, and hence, requiring a sizable negative angular momentum contribution. This component, as well as singlet and non-singlet parts are calculated in the Next-to-Leading order in QCD. We speculate that the gluon contribution to the spin of proton is in the order of 50%. Furthermore, we have determined the polarized valon distribution in a nucleon.

• OSTI ID: 21063961
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 915; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DEUTERONS
DISTRIBUTION
FOUR MOMENTUM TRANSFER
GLUONS
NEUTRONS
ORBITAL ANGULAR MOMENTUM
PARTICLE STRUCTURE
POLARIZATION
PROTONS
QUANTUM CHROMODYNAMICS
QUARKS
SPIN
STRUCTURE FUNCTIONS
VALENCE