Chiral symmetry breaking in quenched massive strong-coupling four-dimensional QED

We present results from a study of subtractive renormalization of the fermion propagator Dyson-Schwinger equation (DSE) in massive strong-coupling quenched four-dimensional QED. The results are compared for three different fermion-photon proper vertex Ansa$uml---tze: bare ${{γ}}^{{{μ}}}$, minimal Ball-Chiu, and Curtis-Pennington Ansa$uml---tze. The procedure is straightforward to implement and numerically stable. This is the first study in which this technique is used and it should prove useful in future DSE studies, whenever renormalization is required in numerical work.