Current algebra and partial symmetry.—I: (SU4)W

The algebra of the good operators of Fubini is studied. The commutators of the positive-parity currents define the W-spin algebra and are saturated with a finite set of states for both baryons and mesons, a procedure which is shown to be correct to(Formula presented.). Schwinger's phenomenological coupling of ρ, π to nucleons is thereby recovered. The negative-parity currents are subjected to a generalized partial-conservation hypothesis (PCAC for the axial current and a generalized PCTC for the negative-parity tensor currents). The algebra implies that the divergences of these currents are coupled to the mesons through the single constant fπ which appears in the conventional PCAC, despite the mass differences for the mesons. The value of fπ is determined by the algebra of the negative-parity currents through the Kawarabayashi-Suzuki relation. We then recover Schwinger's estimate(Formula presented.) in the manner of Freund. We also recover Schwinger's estimate for the isovector part of the magnetic moments. However the isoscalar part must be modified. © 1968, Società Italiana di Fisica. All rights reserved.SCOPUS: ar.j