HIGHER RESONANCE CONTAMINATION OF PI-NN COUPLINGS OBTAINED VIA THE 3-POINT FUNCTION-METHOD IN QCD SUM-RULES

We investigate the size of potential higher pseudoscalar resonance con taminations of the estimates of isospin-conserving and isospin-violati ng pi NN couplings obtained using the three-point function method in Q CD sum rules. For the isospin-conserving case it is shown that convent ional models of the isovector pseudoscalar spectral function imply res onance decay constants large enough to create significant contaminatio ns, and that assuming these models are incorrect, and that the decay c onstants are actually much smaller, implies physically implausible val ues for the flavor-breaking quark condensate ratios. For the isospin-v iolating case it is shown explicitly that such resonance contamination is unavoidably present and precludes using the three-point function m ethod as a means of estimating the at present unmeasured isospin-viola ting pi NN couplings.