On the evaluation of sunset-type Feynman diagrams

We introduce an efficient configuration space technique which allows one to compute a class of Feynman diagrams which generalize the scalar sunset top ology to any number of massive internal lines. General tensor vertex struct ures and modifications of the propagators due to particle emission with van ishing momenta can be included with only a little change of the basic: tech nique described for the scalar case, We discuss applications to the computa tion of n-body phase space in D-dimensional space-time. Substantial simplif ications occur for odd space-time dimensions where the final results can be expressed in closed form through elementary functions. We presl:nt explici t analytical formulas for three-dimensional space-time. (C) 1999 Elsevier S cience B.V.