Kaon nonleptonic decays and chiral-symmetry breaking

A consistent formulation of current algebra and pion partial conservation of axial-vector current is given for the kaon nonleptonic weak decays K→2π and K→3π. This includes evaluation of kaon σ terms and Δ I=1/2 and Δ I=3/2 contributions to the weak current-current Hamiltonian. A large meson σ term, ${\sigma }_{KK}~2{m_{\pi }}^2$, apparently is necessary to explain the $K_{2\pi }$ and $K_{3\pi }$ measured decay parameters. The hyperon nonleptonic decays are then reexamined and also shown to be compatible with a large value for ${\sigma }_{KK}$. Implications for the (3,3̄) chiral-symmetry-breaking model and for octet dominance of the weak Hamiltonian are then discussed.