Analytical and numerical methods for massive two-loop self-energy diagrams

Algebraic-Numerical Evaluation of Feynman Diagrams: Two-Loop Self-Energies

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 infra...

Two-loop self-energy diagrams worked out with NDIM

In this work we calculate two two-loop massless Feynman integrals pertaining to self-energy diagrams using NDIM (Negative Dimensional Integration Method). We show that the answer we get is 36-fold degenerate. We then consider special cases of exponents for propagators and the outcoming results compared with known ones obtained via traditional methods. PACS numbers: 02.90+p, 03.70+k, 12.38.Bx Sh...

Two-loop and n-loop vertex corrections for eikonal diagrams with massive partons

We present the ultraviolet poles and finite terms of two-loop vertex corrections for diagrams with massive partons in the eikonal approximation. We discover and prove that the results for a set of the corrections generalize to n-loop eikonal diagrams. These results will enhance theoretical understanding and allow greater calculational accuracy for the many partonic processes where the eikonal a...

Two - loop sunset diagrams with three massive lines

In this paper, we consider the two-loop sunset diagram with two different masses, m and M , at spacelike virtuality q2 = −m2. We find explicit representations for the master integrals and an analytic result through O(ε) in d = 4 − 2ε space-time dimensions for the case of equal masses, m = M . PACS: 11.15.-q, 12.38.Bx

On the New Method of Computing Two-loop Massive Diagrams