Dynamical breaking to special or regular subgroups in the SO(N) Nambu-Jona-Lasinio model

Abstract

It was recently shown that in four-dimensional SU(N) Nambu-Jona-Lasinio (NJL) type models, the SU(N) symmetry breaking into its special subgroups is not special but much more common than that into the regular subgroups, where the fermions belong to complex representations of SU(N). We perform the same analysis for the SO(N) NJL model for various N with fermions belonging to an irreducible spinor representation of SO(N). We find that the symmetry breaking into special or regular subgroups has some correlation with the type of fermion representations; i.e. complex, real, pseudo-real representations.