Further remarks on electroweak moments of baryons and manifestations of broken SU(3)

Abstract

The role of nonvalence, {\it e.g.} sea quarks and/or meson degrees of freedom in static and quasistatic baryon electroweak observables, is discussed within the phenomenological sum rule approach. The inclusion of nonvalence degrees of freedom in the analysis of baryon magnetic moments explains extremely strong violation of the standard SU(6) symmetry-based quark-model prediction for the magnetic moment ratio $R_{\Sigma /\Lambda}=(\Sigma^{+} + 2\Sigma^{-})/(-\Lambda) \simeq .23$, while the value $R_{\Sigma /\Lambda}(SU(6))= 1$ corresponds to the nonrelativistic quark model. We also obtain $F/D=.72$ for the quark-current-baryon coupling $SU(3)_{f}$ ratio. The implications for the "strangeness" magnetism of the nucleon and for weak axial-to-vector coupling constant relations measured in the lowest octet baryon $\beta$-decays are discussed. The latter shows up the possible role of the induced second-class form factor (the "weak- electricity", or pseudotensor form factor) in the extraction of the $(g_1/f_1)$-values from the hyperon's $\beta$-decay data.