Four-body chiral order parameters in the massless fermion phase

The fermion four-point functions and condensates as the chiral symmetry order parameters are calculated analytically in U (1) gauge theory in the massless phase. It is shown that in leading order of the loop expansion of the effective action, there is a critical coupling for the nonperturbative parity-invariant chirality-changing four-fermion functions; this critical coupling, however, is the same as that for dynamical mass generation. Therefore there is no breaking of chiral symmetry through the condensation of four-fermion functions below the critical coupling for dynamical mass generation for the fermions. 1996 The American Physical Society.