Symmetry limit properties ofa priori mixing amplitudes fornon-leptonic and weak radiative decays ofhyperons

Abstract

We show that, even if a priori mixings of positive-parity butflavour-violating eigenstates are allowed in physical hadrons, in the strongflavour symmetry limit the mixing angle will drop out of the matrixelements of the Yukawa and electromagnetic Hamiltonians that lead tonon-leptonic and weak radiative decays of hyperons in this scheme.We compare this result with related theorems for the same W-mediateddecays and give a concrete example of this behaviour by considering theU-spin symmetry of baryons and the U-doublet formed by p andΣ+.