Abstract :
We consider the N = 2 supersymmetric gauge theory with gauge group SU(2) and use the superfield formalism to calculate the instanton field explicitly. We suggest and check an N = 2 supersymmetric effective vertex encoding instanton-induced effects. This vertex produces an effective low-energy Lagrangian for light fields, whose leading term in the derivatives coincides with the one-instanton-induced term of the Seiberg-Witten exact solution of the model. We calculate the full effective Lagrangian, including all powers of field derivatives, as induced by one instanton.
