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## Flowing between string vacua for the critical non-Abelian vortex with a deformation of N = 2 Liouville theory

It has been shown that non-Abelian solitonic vortex string supported in four-dimensional (4D) N = 2

supersymmetric QCD (SQCD) with the U(2) gauge group and Nf =4 quark flavors becomes a critical

superstring. This string propagates in the ten-dimensional space formed by a product of the flat 4D space

and an internal space given by a Calabi-Yau noncompact threefold, namely, the conifold. The spectrum of

low-lying closed string states was found and interpreted as a spectrum of hadrons in 4D N = 2 SQCD. In

particular, the lowest string state appears to be a massless Bogomol’nyi-Prasad-Sommerfield (BPS) baryon

associated with the deformation of the complex structure modulus b of the conifold. It was recently shown

that the Coulomb branch of the associated string sigma model which opens up at strong coupling can be

described by N = 2 Liouville theory. Building on these results we switch on quark masses in 4D N = 2

SQCD and study the interpolation of the initial U(2) SQCD with Nf = 4 quarks to the final SQCD with

the U(4) gauge group and Nf =supersymmetry 8 quarks. To find the true string vacuum which arises due to the mass

deformation we solve the effective supergravity equations of motion associated with the deformed world

sheet Liouville theory. We show that the massless BPS baryon b survives the deformation and that finding

of the spectrum of low-lying massive hadrons in the final SQCD is linked to the Calogero problem.