MODULAR INVARIANCE AND EXACT WILSONIAN ACTION OF N=2 SYM THEORY

We construct modular invariants on MSU\(2\), the moduli space of quantum vacua of N = 2 supersymmetric Yang-mills theory with gauge group SU(2). We also introduce the nonchiral function K\(A,A¯\) = 2απeϕSW-ϕ/2, where eϕSW is the Seiberg-Witten metric, eϕ is the Poincaré metric on MSU\(2\) and α is a regularization scheme-dependent constant. It turns out that K\(A,A¯\) has all the expected properties of the next to leading term in the Wilsonian effective action S[A,A¯] whose modular properties are considered in the framework of the dimensional regularization.