Hadrons in N = 2 supersymmetric QCD from non-Abelian string on 2D black hole

Physical Review D - Particles, Fields, Gravitation and Cosmology. 2026. Vol. 114. Article 046006.

Ievlev E., Marshakov A., Sumbatian G., Yung A

We continue the study of non-Abelian vortex string in 4D N =2 supersymmetric QCD (SQCD) as
critical superstring, and extend this analysis to UðNÞ gauge theory with arbitrary even N and Nf = 2N
number of quarks. We introduce a special mass deformation and show that the SQCD hadron spectrum is
still given by the string spectrum on the 2D N = 2 supersymmetric black hole. We perform a cross-check
by computing the multiplicity of hadronic states of the high-energy part of the spectrum both from string
and field theory pictures. We also clarify the spontaneous breaking of the global flavor symmetry by the
vacuum expectation value of the massless baryon. We finally claim that phase diagram of N = 2 SQCD
with Nf = 2N consists of the Higgs phase at weak coupling and string/hadronic phase at strong coupling,
separated by phase transition, and is seen as a conifold transition from the string theory point of view

Keywords: string theory, gauge theories, supersymmetry, Sigma Models, vortices