Instantons, higher-derivative terms, and nonrenormalization theorems in supersymmetric gauge theories

We discuss the contribution of ADHM multi-instantons to the higher-derivative terms in the gradient expansion along the Coulomb branch of N = 2 and N = 4 supersymmetric SU(2) gauge theories. In particular, using simple scaling arguments, we confirm the Dine-Seiberg nonperturbative nonrenormalization theorems for the 4-derivative/8-fermion term in the two finite theories (N = 4, and N = 2 with NF = 4).