EFFECTIVE FERMION MODELS WITH DYNAMICAL SYMMETRY-BREAKING

Effective many-fermion models with finite momentum cutoff in the regim e of dynamical symmetry breaking are considered as low-energy approxim ation to the action of quantum chromodynamics. The quasilocal interact ion vertices responsible for the formation of dynamic fermion mass are classified for these models in the near-critical region of coupling c onstants. It is shown that in four-dimensional space not only the 4-fe rmion interaction but also vertices with six and eight fermion fields and any number of derivatives are also important. In the mean field ap proximation an equation is derived for the critical surface for the co upling constants of the effective fermion action. The role of the lead ing interaction vertices in forming the physical parameters that do no t depend on the momentum cutoff is discussed.