A primary universal vector and axial-vector interaction theory is proposed for strong-interaction phenomena. It is shown that such a hypothesis leads to a definite relation between vector and pseudoscalar coupling constants, which predict the $S$- and $P$-wave pion-nucleon scattering lengths, in good agreement with experiments. The ratio of $\pi$-meson to $\rho$-meson masses is also predicted, which agrees well with the observed value.

• Received 20 October 1967

DOI:https://doi.org/10.1103/PhysRevLett.20.79