Instanton induced Green functions in the superfield formalism

We discuss in detail the supersymmetric instanton calculus of NSVZ and extend it to chiral matter fields in the adjoint representation. The constant Green functions induced by the instanton of supersymmetric SU(2) gauge theories are calculated systematically for the cases with and without scalar vev's bigger than the scale of the gauge theory and for nonvanishing small masses of chiral fields. One-instanton contributions to the Green functions containing four fields without large vevs would disturb clustering; but they are argued to vanish; two-instanton effects then lead to a pattern which quantitatively agrees with factorization and the anomaly relation. (orig.)