Hyperon decays revisited

We examine the standard quantum-chromodynamics-inspired description of nonleptonic hyperon decays. We point out that the discrepancy between $s$- and $p$-wave amplitudes which emerged from a PCAC (partial conservation of axial-vector current) analysis cannot be cured by the inclusion of factorizable diagrams. We include anomalous contributions to the axial-vector current divergence which appear in the presence of the effective local Fermi interaction. Like factorizable diagrams, these preserve the successful results of PCAC for $s$-wave amplitudes, but are insufficient to give a quantitatively satisfactory description. We estimate the decay rates for ${\Omega }^{-}\to {\Xi }^{*}\pi$ and ${\Xi }^0{l}^{-}{\nu }_l$ in view of further tests of the standard model.