On the Four-Dimensional Formulation of Dimensionally Regulated Amplitudes

Understand

We propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes.

• In our formulation particles propagating inside the loop are represented by massive internal states regulating the divergences.
• The latter obey Feynman rules containing multiplicative selection rules which automatically account for the effects of the extra-dimensional regulating terms of the amplitude.
• The equivalence between the FDF and the Four Dimensional Helicity scheme is discussed.