Analytical result for dimensionally regularized massless on-shell double box

The dimensionally regularized massless on-shell double box Feynman diagram with powers of propagators equal to one is analytically evaluated for general values of the Mandelstam variables s and t. An explicit result is expressed either in terms of polylogarithms Li-a( - t/s), up to a = 4, and generalized polylogarithms S-a,S-b(- t/s), with a = 1,2 and b = 2, or in terms of these functions depending on the inverse ratio, s/t. (C) 1999 Published by Elsevier Science B.V. All rights reserved.