PLANAR EQUIVALENCE: FROM TYPE 0 STRINGS TO QCD

This talk is about the planar equivalence between gluodynamics (super-Yang-Mills theory) and a non-supersymmetric “orientifold field theory.” We outline an “orientifold” large N expansion, analyze its possible phenomenological consequences in one-flavor massless QCD, and make a first attempt at extending the correspondence to three massless flavors. An analytic calculation of the quark condensate in one-flavor QCD starting from the gluino condensate in gluodynamics is thoroughly discussed.