Tests of SU(3) Symmetry-Breaking for Baryonic Beta Transitions in the Standard Model

It is generally assumed that deviations from flavor SU(3) symmetry arise entirely from quark mass-differences, reflected in the mass splittings between strange and nonstrange members of the same SU(3) multiplet. Under this assumption, a parametrization is proposed which expresses the ratios of Gamow-Teller to Fermi matrix elements for nucleon and hyperon beta decays entirely in terms of two SU(3)-invariant coupling constants $F$ and $D$ and two parameters $\gamma$ and $\delta$ representing SU(3) breaking effects. Therefore, in principle, measurement of this ratio for any four beta-transitions should yield all four parameters. Available data do not show any evidence for SU(3) breaking. Improved measurements, also for transitions not previously measured, would provide more stringent tests.