It was recently shown that non-Abelian vortex strings supported in a version of four-dimensional N=2 supersymmetric QCD become critical superstrings. In addition to four translational moduli, non-Abelian strings under consideration have six orientational and size moduli. Together they form a ten-dimensional target space required for a superstring to be critical, namely, the product of the flat four-dimensional space and conifold - a noncompact Calabi-Yau threefold. In this paper we report on further studies of low-lying closed string states that emerge in four dimensions and identify them as hadrons of our four-dimensional N=2 QCD. We use the approach based on little string theory, describing the critical string on the conifold as a noncritical c=1 string with the Liouville field and a compact scalar at the self-dual radius. In addition to the massless hypermultiplet found earlier we observe several massive vector multiplets and a massive spin-2 multiplet, all belonging to the long (non-BPS) representations of N=2 supersymmetry in four dimensions. All the above states are interpreted as baryons formed by a closed string with confined monopoles attached. Our construction presents an example of a "reverse holography."
Bibliographical noteFunding Information:
The authors are grateful to Edwin Ireson for useful discussions and to Efrat Gerchkovitz and Avner Karasik for helpful communications. This work is supported in part by DOE Award No. DE-SC0011842. The work of A. Y. was supported by William I. Fine Theoretical Physics Institute at the University of Minnesota and by Russian Foundation for Basic Research Grant No. 18-02-00048.
© 2018 authors. Published by the American Physical Society.