Light fermion mass generation in dynamical symmetry breaking

We reconsider the question of mass generation for fermions coupled to a set of gauge bosons when the latter get their masses through the Goldstone bosons originating in a simple (i.e. not extended) technicolor sector. The fermion global chiral symmetries are broken by including four-fermion interactions. We find that the system can be nonperturbatively unstable under fermion mass fluctuations driving the formation of an effective coupling between the technigoldstone bosons and the ordinary fermions. Minimization of an effective action for the corresponding composite operators describes then dynamical generation of light fermion masses of order M exp(-k/g^2), where M is some cutoff mass.