N=1* model and glueball superpotential from Renormalization-Group-improved perturbation theory

A method for computing the low energy non-perturbative properties of SUSY GFT, starting from the microscopic lagrangian model, is presented. The method relies on i. covariant SUSY Feynman graph techniques, adapted to low energy, and ii. the Renormalization-Group-improved perturbation theory. We apply the method to calculate the effective gauge coupling in N=2 SYM model and the glueball superpotential in N=1 SYM. While in the first case one obtains only the one-loop perturbatively exact result, in the second case one obtains a potential of the Veneziano-Yankielowicz type