Automatic Loop Calculations with FeynArts, FormCalc, and LoopTools

This article describes three Mathematica packages for the automatic calculation of one-loop Feynman diagrams: the diagrams are generated with FeynArts, algebraically simplified with FormCalc, and finally evaluated numerically using the LoopTools package. The calculations are performed analytically as far as possible, with results given in a form well suited for numerical evaluation. The latter is straightforward with the utility programs provided by FormCalc (e.g. for translation into Fortran code) and the implementations of the one-loop integrals in LoopTools. The programs are also equipped for calculations in supersymmetric models.