Color-flavor reflection in the continuum limit of two-dimensional lattice gauge theories with scalar fields

We address the interplay between local and global symmetries in determining the continuum limit of twodimensional lattice scalar theories characterized by SO(Nc) gauge symmetry and non-Abelian O(N-f) global invariance. We argue that, when a quartic interaction is present, the continuum limit of these models corresponds in some cases to the gauged nonlinear ?? model field theory associated with the real Grassmannian manifold SO(N-f)/(SO(N-c) x SO(N-f - N-c)), which is characterized by the invariance under the color-flavor reflection N-c <-> N-f - N-c. Monte Carlo simulations and finite-size scaling analyses, performed for N-f = 7 and several values of N-c, confirm the emergence of the color-flavor reflection symmetry in the scaling limit and support the identification of the continuum limit.