APPLICATION OF A COORDINATE-SPACE METHOD FOR THE EVALUATION OF LATTICE FEYNMAN DIAGRAMS IN 2 DIMENSIONS

We apply a new coordinate-space method for the evaluation of lattice F eynman diagrams suggested by Luscher and Weisz to field theories in tw o dimensions. Our work is presented for the theories with massless pro pagators. The main idea is to deal with the integrals in position spac e by making use of the recursion relation for the free propagator G(x) which allows us to compute the propagator recursively by its values a round the origin. It turns out that the method is very efficient and g ives very precise results. We illustrate the technique by evaluating a number of two- and three-loop diagrams explicitly. (C) 1998 Elsevier Science B.V.