Vertex diagrams for the QED form factors at the 2-loop level

We carry out a systematic investigation of all the 2-loop integrals occurring in the electron vertex in QED in the continuous D-dimensional regularization scheme, for on-shell electrons, momentum transfer t = -Q(2) and finite squared electron mass m(e)(2) = a. We identify all the master integrals (MIs) of the problem and write the differential equations in Q(2) which they satisfy. The equations are expanded in powers of is an element of = (4 - D)/2 and solved by the Euler's method of the variation of the constants. As a result, we obtain the coefficients of the Laurent expansion in c of the MIs up to zeroth order expressed in close analytic form in terms of harmonic polylogarithms. (C) 2003 Elsevier Science B.V. All rights reserved.