V-A theory and the decay of the Λ hyperon

Abstract

The decay of the Λ hyperon is studied within the framework of the chirality-invariant four-fermion interaction. It is shown that the branching ratio of the charged and neutral modes, the s- to p-wave emission, as well as the sign and magnitude of the asymmetry parameter of the p+π⁻ decay mode, can be understood on the basis of the V-A theory. Improvements upon the Born approximation, using dispersion theory, indicate that these conclusions are not invalidated by taking into account the pion-nucleon interaction.