CALCULATION OF G(PI-NS11) AND G(ETA-NS11) COUPLINGS IN QCD SUM-RULES

We calculate the coupling constants g(pi NS11) and g(eta NS11) using Q CD sum rules in the presence of an external meson field. A covariant d erivative is introduced within the S-11 interpolating field so that in the nonrelativistic limit the field dominantly reduces to two quarks in the s-wave state and one quark in the p-wave state. Our result for the couplings obtained by further making use of the soft-meson theorem qualitatively agrees with its phenomenological value extracted from t he S-11(1535) decay width. The prediction for the couplings, however, depends on the value of the quark-gluon condensate ((q) over bar g(s) sigma.Gq), which is also important in the calculation of the S-11(1535 ) mass itself within the sum rule approach.