Kμ2Decay and Leptonic Decay of Hyperons

Abstract

The partial lifetime of $K\to \mu +\nu$ is calculated by dispersion techniques assuming that the $K$ meson is pseudoscalar and that the relevant Fermi interactions are of the $V-A$ type. The results are compared with experiments and it is concluded that the renormalized axial vector coupling which is responsible for the leptonic decay of hyperons is much smaller than the usual universal Fermi interaction.