KAON WEAK DECAYS IN CHIRAL THEORIES

Abstract

The ten nonleptonic weak decays K→2π, K→ 3π, KL→2γ, KS→2γ, KL→π02γ, are predicted for a chiral pole model based on the linear sigma model theory which automatically satisfies the partial conservation of axial current (PCAC) hypothesis. These predictions, agreeing with data to the 5% level and containing no or at most one free parameter, are compared with the results of chiral perturbation theory (ChPT). The latter ChPT approach to one-loop level is known to contain at least four free parameters and then predicts a KL→π0γγ rate which is 60% shy of the experimental value.