MASS PERTURBATIONS IN TWISTED N=4 SUPERSYMMETRIC GAUGE-THEORIES

Mass perturbations of the twisted N = 4 supersymmetric gauge theory co nsidered by Vafa and Witten to test S-duality are studied for the case of Kahler four-manifolds. It is shown that the resulting mass-perturb ed theory can be regarded as an equivariant extension associated to a U(1) symmetry of the twisted theory, which is only present for Kahler manifolds. In addition, it is shown that the partition function, the o nly topological invariant of the theory, remains invariant under the p erturbation. (C) 1998 Elsevier Science B.V.