Analytical result for dimensionally regularized massless on-shell planar triple box

The dimensionally regularized massless on-shell planar triple box Feynman diagram with powers of propagators equal to one is analytically evaluated for general values of the Mandelstam variables s and t in a Laurent expansion in the parameter epsilon = (4 - d)/2 of dimensional regularization up to a finite part. An explicit result is expressed in terms of harmonic polylogarithms, with parameters 0 and 1, up to the sixth order. The evaluation is based on the method of Feynman parameters and multiple Mellin-Bames representation. The same technique can be quite similarly applied to planar triple boxes with any numerators and integer powers of the propagators. (C) 2003 Published by Elsevier B.V.