Superconvergent Dispersion Relations and Vector-Meson-Baryon Couplings

Matrix elements of the equal-time commutators of an octet of vector current densities are considered in the infinite-momentum limit. As a consequence of locality, the Fourier transforms of these matrix elements are polynomials in the components of the momentum transfer. The resulting superconvergent sum rules are saturated with the octet and the decimet of baryons, and are evaluated at the double pole due to vector mesons. A consistent set of approximate equations for vector-meson-baryon couplings is obtained. This set has a unique nontrivial solution for the coupling constants. Together with a meson pole model for the electromagnetic form factors of baryons, these couplings give rise to relations for the form factors which are in good agreement with experiments. They are also consistent with the results obtained on the basis of collinear $U\left(6\right)\mathrm{}$ symmetry.