Properties of Weak Amplitudes in BrokenŨ(12)

Abstract

Weak nonleptonic amplitudes are discussed in the $\tilde{U}\mathrm{}\left(12\right)\mathrm{}$ scheme on the assumption of octet dominance. The contributions to hyperon-decay $S$ waves of spurions of representations higher than 143 of the current ⊗ current product are discussed in detail. In addition to Gell-Mann's relations for hyperon $S$ waves we find that ${\Sigma }^{+}\to n+{\pi }^{+}$ is forbidden in $S$ waves apart from minor kinematical corrections. Possible modifications from a kinetic-energy spurion are also examined. Some remarks concerning consequences of $\mathrm{CP}$ invariance and concerning $K_{{}_{}{}^2{}_{}{}^{}\pi }$ decays are included.