Metastable vacua and D-branes at the conifold

We consider quiver gauge theories arising on D-branes at simple Calabi-Yausingularities (quotients of the conifold). These theories have metastablesupersymmetry breaking vacua. The field theoretic mechanism is basically theone exhibited by the examples of Intriligator, Seiberg and Shih in SUSY QCD. Ina dual description, the SUSY breaking is captured by the presence ofanti-branes. In comparison to our earlier related work, the main improvementsof the present construction are that we can reach the free magnetic range ofthe SUSY QCD theory where the existence of the metastable vacua is on firmfooting, and we can see explicitly how the small masses for the quark flavors(necessary to the existence of the SUSY breaking vacua) are dynamicallystabilized. One crucial mass term is generated by a stringy instanton. Finally,our models naturally incorporate R-symmetry breaking in the non-supersymmetricvacuum, in a way similar to the examples of Kitano, Ooguri and Ookouchi.Comment: 26 pages, harvmac. v2.: Comments and references adde