We study confinement in softly broken N = 2 SUSY QCD with gauge group SU(Nc) and Nf hypermultiplets of fundamental matter (quarks) when the Coulomb branch is lifted by small mass of adjoint matter. Concentrating mostly on the theory with SU(3) gauge group we discuss the N = 1 vacua which arise in the weak coupling at large values of quark masses and study flux tubes and monopole confinement in these vacua. In particular we find the BPS strings in SU(3) gauge theory formed by two interacting U(1) gauge fields and two scalar fields generalizing ordinary Abrikosov-Nielsen-Olesen vortices. Then we focus on the SU(3) gauge theories with Nf = 4 and Nf = 5 flavors with equal masses. In these theories there are N = 1 vacua with restored SU(2) gauge subgroup in quantum theory since SU(2) subsectors are not asymptotically free. We show that although the confinement in these theories is due to Abelian flux tubes the multiplicity of meson spectrum is the same as expected in a theory with non-Abelian confinement.
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We are grateful to P. Arseev, N. Fedorov, A. Gorsky, K. Konishi, A. Morozov, V. Rubakov, M. Shifman and D. Tong for useful discussions. Our special thanks are to A. Vainshtein for numerous illuminating discussions and critical comments on the earlier version of this paper. A.Y. would like to thank the Theoretical Physics Institute of the University of Minnesota where part of this work has been done for hospitality and support. The work was supported by Russian Foundation for Basic Research under the grants No. 00-02-16477 (A.M.) and No. 02-02-17115 (A.Y.), by INTAS grant No. 00-00334 and by the grants for support of scientific schools No. 00-15-96566 (A.M.) and No. 00-15-96611 (A.Y.).