Phenomenological analysis of the nucleon spin contents and their scale dependence

Journal Article · Tue Apr 01 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.074011· OSTI ID:21249936

Wakamatsu, M; Nakakoji, Y ^[1]

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1. Department of Physics, Faculty of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

In the past few years, a great deal of evidence has accumulated which indicates that the gluon polarization inside the nucleon is likely to be small at least at the low renormalization scales. On the other hand, the recent lattice QCD analyses suggest that the net orbital angular momentum carried by the quarks is nearly zero. There is also some indication, noted by Brodsky and Gardner based on the COMPASS observation of small single-spin asymmetry on the isoscalar deuteron target, that the gluon orbital angular momentum inside the nucleon is likely to be small. Naively combining all these observations, we are led to a rather embarrassing conclusion that the nucleon constituents altogether do not carry an adequate amount of angular momentum saturating the total nucleon spin. We show that this somewhat confused state of affairs can be cleared up only by paying careful attention to the scale dependencies of the nucleon spin decomposition.

• OSTI ID: 21249936
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 7 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
COMPASS-D TOKAMAK
DECOMPOSITION
DEUTERIUM TARGET
GLUONS
NUCLEONS
ORBITAL ANGULAR MOMENTUM
POLARIZATION
QUANTUM CHROMODYNAMICS
QUARKS
RENORMALIZATION
SPIN