R Duality and "instead-of-confinement" mechanism in N=1 supersymmetric QCD

We consider N=2 SQCD with the U(N) gauge group and N _f flavors (N _f>N) perturbed by an N=2 breaking deformation-a small mass term μ for the adjoint matter. We study r-vacua, with the constraint 23N _f<r≤N. At large values of the parameter ξ∼μm (m is a typical value of the quark masses) r quark flavors condense, by construction. The effective low-energy theory with the gauge group U(r)×U(1)N ^-r is at weak coupling. Upon reducing ξ the original theory undergoes a crossover transition from weak to strong coupling. As the original theory becomes strongly coupled, at low energies it is described by a weakly coupled infrared-free dual theory with the gauge group U(N _f-r) ×U(1)N ^-N _f ⁺r and N _f light dyon flavors. These dyons condense triggering formation of non-Abelian strings which still confine monopoles, rather than quarks, contrary to naive duality arguments. "Instead-of-confinement" mechanism for quarks and gauge bosons of the original theory takes place: screened quarks and gauge bosons of the original theory decay, on curves of the marginal stability (CMS), into confined monopole-antimonopole pairs that form stringy mesons. Next, we increase the deformation parameter μ thus decoupling the adjoint fields. Then our theory flows to N=1 SQCD. The gauge group of the dual theory becomes U(N _f-r). We show that the dual theory is weakly coupled if we are sufficiently close to the Argyres-Douglas point. The "instead-of- confinement" mechanism for quarks and gauge bosons survives in the limit of large μ. It determines low-energy non-Abelian dynamics in the r-vacua of N=1 SQCD.