One-instanton tests of the exact results in N = 2 supersymmetric QCD

We use the microscopic instanton calculus to determine the one-instanton contribution to the quantum modulus u3 = 〈Tr(ø3)〉 in N = 2 SU(Nc) supersymmetric QCD with Nf < 2Nc fundamental flavors. This is compared with the corresponding prediction of the hyperelliptic curves which are expected to give exact solutions in this theory. The results agree up to certain regular terms which appear when Nf ≥ 2Nc − 3. The curve prediction for these terms depends upon the curve parameterization which is generically ambiguous when Nf ≥ Nc. In SU(3) theory our instanton calculation of the regular terms is found to disagree with the predictions of all of the suggested curves. For this theory we employ our results as input to improve the curve parameterization for Nf = 3,4,5.