MONOPOLES, DUALITY AND CHIRAL-SYMMETRY BREAKING IN N=2 SUPERSYMMETRICQCD

We study four dimensional N = 2 supersymmetric gauge theories with mat ter multiplets. For all such models for which the gauge group is SU(2) , we derive the exact metric on the moduli space of quantum vacua and the exact spectrum of the stable massive states. A number of new physi cal phenomena occur, such as chiral symmetry breaking that is driven b y the condensation of magnetic monopoles that carry global quantum num bers. For those cases in which conformal invariance is broken only by mass terms, the formalism automatically gives results that are invaria nt under electric-magnetic duality. In one instance, this duality is m ixed in an interesting way with SO(8) triality.