Dimensional regularization and mass singularities

We demonstrate how the continuous-dimension method can be employed to simultaneously regularize infrared photonic divergences and electron mass singularities (i.e., terms which diverge in the limit mₑ→0). Using this technique, a photon mass need not be introduced and the electron mass can be set equal to zero from the start, thereby simplifying radiative-corrections calculations. Transition rates obtained in this approach are functions of the regularizing parameter n (the dimension of space-time). To determine which of these rates are finite in the limit n→4, we employ the theorem on the cancellation of mass singularities. Even for transition rates which contain residual mass singularities, this method is useful for extracting leading logarithmic corrections. The formalism of this approach is illustrated for the decay of a charged intermediate vector boson.