Scalar-meson-baryon coupling constants in QCD sum rules

The external-field QCD sum rules method is used to evaluate the coupling constants of the light isoscalar-scalar meson (sigma or epsilon) to the Lambda,Sigma, and Xi baryons. It is shown that these coupling constants as calculated from QCD sum rules are consistent with SU(3) flavor relations, which leads to a determination of the F/(F+D) ratio of the scalar octet assuming ideal mixing: we find alpha(s)equivalent to F/(F+D)=0.55. The coupling constants with SU(3) breaking effects are also discussed.