Phase Structure and Dilaton in QED with Four-Fermion Interaction

Abstract

The chiral phase transition of QED plus four-fermion interaction is studied through the quenched planar (ladder) Schwinger-Dyson equation. We derive the critical line and the scaling relation near the critical line from the analytical solution which is valid for the whole coupling region including the pure four-fermion limit. Along the full critical line we find no dilaton in the fermion-antifermion scattering amplitude and also in the effective potential approach.