Gauge covariant fermion-photon vertex in quenched, massless three dimensional quantum electrodynamics

Full text: We consider the problem of designing an Ansatz for the transverse part of the fermion-photon vertex in QED{sub 3}. Our work is based on that of Ball and Chiu, who consider restrictions placed on the vertex by the U(1) Ward identity, and on subsequent modifications which attempt to satisfy the Landau-Khalatnikov transformation rules. A class of vertex Ansaetze including that proposed by Dong et al is tested using the gauge invariance of the vacuum polarisation scalar 3 refs.