Phenomenological analysis of the nucleon spin contents and their scale dependence
- 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, Vol. 77, Issue 7; Other Information: DOI: 10.1103/PhysRevD.77.074011; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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