Two-loop three-point diagrams with irreducible numerators

Abstract

We study the problem of calculating two-loop three-point diagrams with irreducible numerators (i.e. numerators which cannot be expressed in terms of the denominators). For the case of massless internal particles and arbitrary (off-shell) external momenta, exact results are obtained in terms of polylogarithms. We also consider the tensor decomposition of two-loop three-point diagrams, and show how it is connected with irreducible numerators.

Comments: 12 pages, latex, 3 figures, ps-file available at ftp://vsfys1.fi.uib.no/davydychev/bergen94-17.ps