Algebraic-numerical evaluation of Feynman diagrams: two-loop self-energies Original Research Article

A recently proposed scheme for numerical evaluation of Feynman diagrams is extended to cover all two-loop two-point functions with arbitrary internal and external masses. The adopted algorithm is a modification of the one proposed by F.V. Tkachov and it is based on the so-called generalized Bernstein functional relation. On-shell derivatives of self-energies are also considered and their infrared properties analyzed to prove that the method which is aimed to a numerical evaluation of massive diagrams can handle the infrared problem within the scheme of dimensional regularization. Particular care is devoted to study the general massive diagrams around their leading and non-leading Landau singularities.