Weinberg's first sum rule applied to the axial-vector currents is shown to split into two separately valid sum rules if the usual assumptions concerning SU(3) mixing are adopted. New relations among masses, coupling constants, and mixing angles are obtained in the meson-dominance approximation, e.g., $\frac{F_K}{F_{\pi }}=1\mathrm{}$, and the implications are discussed.

• Received 1 December 1967

DOI:https://doi.org/10.1103/PhysRevLett.20.513