DYNAMIC MASS GENERATION IN QED3 AND THE 1/N EXPANSION

The dynamical generation of fermion masses is studied in three-dimensional QED as a function of the number of fermion flavours, N, by solving the Schwinger-Dyson equation for the full fermion propagator in the Landau gauge. The non-perturbative fermion-boson vertex of our previous analysis, which satisfies the relevant Ward-Takahashi identity, is extended to include transverse parts that reproduce the 1/N perturbative result. Nevertheless, there is no sign of the critical behaviour found in the simple ladder approximation that neglects wavefunction renormalization. Chiral symmetry continues to be broken for all values of N.