Existing analyses of baryon semileptonic decays indicate the presence of a small $SU(3)$ symmetry breaking effect in hyperon semileptonic decays. However, to provide evidence for $SU(3)$ symmetry breaking, one needs a relation similar to the Gell-Mann–Okubo baryon mass formula satisfied to within a few percent, showing evidence for $SU(3)$ symmetry breaking in the divergence of the vector current matrix element. In this paper, we shall present a similar Gell-Mann–Okubo relation for the hyperon semileptonic decay axial vector form factors. Using these relations and the measured axial vector current for vector current form factor ratios, we show that the amount of $SU(3)$ symmetry breaking in hyperon semileptonic decaysis 5–11%.

• Received 17 October 2012

DOI:https://doi.org/10.1103/PhysRevD.87.016002