Pentagon functions for massless planar scattering amplitudes

Gehrmann, T.  (0000 0004 1937 0650, Physik-Institut, Universität Zürich, Wintherturerstrasse 190, CH-8057, Zürich, Switzerland) ; Henn, J. (0000 0001 1941 7111, PRISMA Cluster of Excellence, Institute of Physics, Johannes Gutenberg University, D-55099, Mainz, Germany) (MPI für Physik, Werner-Heisenberg-Institut, München, Germany) ; Lo Presti, N. (0000 0000 8700 0572, Institute for Particle Physics Phenomenology, Durham University, Durham, DH1 3LE, U.K.)

17 October 2018

Abstract: Loop amplitudes for massless five particle scattering processes contain Feynman integrals depending on the external momentum invariants: pentagon functions. We perform a detailed study of the analyticity properties and cut structure of these functions up to two loops in the planar case, where we classify and identify the minimal set of basis functions. They are computed from the canonical form of their differential equations and expressed in terms of generalized polylogarithms, or alternatively as one-dimensional integrals. We present analytical expressions and numerical evaluation routines for these pentagon functions, in all kinematical configurations relevant to five-particle scattering processes.


Published in: JHEP 1810 (2018) 103
Published by: Springer/SISSA
DOI: 10.1007/JHEP10(2018)103
arXiv: 1807.09812
License: CC-BY-4.0



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