Simple meson-pole models for nonleptonic $K$ and $\eta$ decays are presented in the context of current-current Lagrangians for the weak and electromagnetic interactions; consistency with low-energy theorems of current algebra is demonstrated and comparison made with experiment. It is shown that violations of the $\Delta I=\frac{1}{2}$ rule may be attributed to $\eta -\pi$ mixing.

• Received 23 August 1968

DOI:https://doi.org/10.1103/PhysRev.178.2190