Dynamical breaking ofU(N) and generation of Chern-Simons term in 4-fermion theories

The phase structure of a three-dimensional four-fermion field theory is considered. It IS shown that forg < 0 both parity and the U(N) invariance of the model are spontaneously broken. For oddN, this leads to the generation of a Chern-Simons term if the fermions interact with a gauge field.Institute of High Energy Physics, Serpukhov. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 92, No. 1, pp. 166–171, July, 1992.