Pion mass and the Cabibbo angle

Abstract

The relation between the Cabibbo angle and the pion mass is analysed in the framework of the Glashow-Weinberg type theory with explicit SU(2) and strangeness breakings, in which the strangeness conservation limit corresponds to massless pions (without any restrictions on the intraisotopic mass splittings of mesons). In this way we find sin 2 θ = (π +F π/ K° K ° ) − 1 2 in good agreement with the experimental value for Z π = Z K.