SU ( 3 ) symmetry breaking in hyperon semileptonic decays

Flavor SU(3) symmetry breaking in the hyperon semileptonic decay form factors is analyzed using the 1/Nc expansion. A detailed comparison with experimental data shows that corrections to f1 are approximately 10%, which agrees with theoretical expectations. Corrections to g1 are compatible with first-order symmetry breaking. A fit to the experimental data allows one to predict the g1 form factor for Ξ 0 → Σ+ decay. The proton matrix element of the T 8 component of the axial current (which is equal to 3F − D in the SU(3) symmetry limit) is found to be ≈ 0.34–0.46. Typeset using REVTEX ∗On leave from Departamento de F́ısica, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000, México, Distrito Federal, Mexico