Dynamically Emergent Flavor in a Confining Theory with Unbroken Chiral Symmetry

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I discuss "truncated" QCD studied recently by Glozman et al. through numerical simulations. For two flavors it was observed that truncation restores the full chiral U(2)× U(2) symmetry of the Lagrangian. Moreover, additional enhancement of the above symmetry connecting representations with distinct Lorentz spins was observed. I argue that the chiral symmetry restoration in a confining theory could entail emergent (extra) dynamical flavors which would show up in the spectrum of color-singlet particles provided their mass ≠ 0. As an example, I consider truncated QCD with a single massless Dirac quark. Assuming the validity of the above observations,I demonstrate how a dynamical SU(2)fl symmetry could emerge for massive spin-1 mesons without contradicting general principles.