I derive a set of generalized Sehgal equations (GSE) which link octet-baryon magnetic moments to quark axial-vector currents in the proton. The equations are shown to be valid in a class of shell models, containing both nonrelativistic and relativistic quark models. The GSE fit magnetic-moment data better than naive quark model formulas, but not perfectly. In best fits to magnetic moments quarks carry a small fraction of the angular momentum of the proton. The precise value of this fraction is poorly determined by these fits: $\Delta u+\Delta d+\Delta s=0.27\mathrm{}\pm 0.23$; this fraction is small compared to unity, but consistent with the recent European Muon Collaboration experiments.

• Received 8 March 1991

DOI:https://doi.org/10.1103/PhysRevD.45.247