Application of conformal mapping and Padé approximants $(ωP's)$ to the calculation of various two-loop Feynman diagrams

Abstract

Feynman diagrams are calculated by means of their Taylor series expansion in terms of external momenta squared. It is demonstrated in various examples that by the application of conformal mapping and Padé approximants, it is possible to obtain high precision results in the spacelike as well as in the timelike region on the cut. Examples are given for two- and three-point functions, but in principle the method is applicable also to four-point functions.