Gauge symmetry and supersymmetry breaking from intersecting branes

We study a system of intersecting NS- and D-branes in type IIA string theory in R9,1. We show that the (3+1)-dimensional non-supersymmetric theory at the intersection has unstable vacua which are long-lived in some regions of the parameter space of brane configurations, and disappear in others. We also comment on the relation of our construction to systems of D- and D¯-branes wrapped around cycles of non-compact Calabi–Yau manifolds and to other related systems.