Two-loop correction to Bhabha scattering - art. no. 053007

We present the two-loop virtual QED corrections to e(+) e(-) --> mu (+) mu (-) and Bhabha scattering in dimensional regularization. The results are ex pressed in terms of polylogarithms. The form of the infrared divergences ag rees with previous expectations. These results are a crucial ingredient in the complete next-to-next-to-leading order QED corrections to these process es. A future application will be to reduce theoretical uncertainties associ ated with luminosity measurements at e(+) e(-) colliders. The calculation a lso tests methods that may be applied to analogous QCD processes.