Multi-instanton calculus inN=2supersymmetric gauge theory. II. Coupling to matter

We further discuss the $N=2\mathrm{}$ superinstantons in SU(2) gauge theory, obtained from the general self-dual solutions of topological charge $n$ constructed by Atiyah, Drinfeld, Hitchin, and Manin (ADHM). We realize the $N=2\mathrm{}$ supersymmetry algebra as actions on the superinstanton moduli. This allows us to recast in concise superfield notation our previously obtained expression for the exact classical interaction between $n$ ADHM superinstantons mediated by the adjoint Higgs bosons, and, moreover, to incorporate $N_F$ flavors of hypermultiplets. We perform explicit one- and two-instanton checks of the Seiberg-Witten prepotentials for all $N_F$ and arbitrary hypermultiplet masses. Our results for the low-energy couplings are all in precise agreement with the predictions of Seiberg and Witten except for $N_F=4\mathrm{}$, where we find a finite renormalization of the coupling which is absent in the proposed solution.