Precise numerical evaluation of the two loop sunrise graph Master Integrals in the equal mass case

Abstract

We present a double precision routine in Fortran for the precise and fast numerical evaluation of the two Master Integrals (MIs) of the equal mass two-loop sunrise graph for arbitrary momentum transfer in d=2 and d=4 dimensions. The routine implements the accelerated power series expansions obtained by solving the corresponding differential equations for the MIs at their singular points. With a maximum of 22 terms for the worst case expansion a relative precision of better than a part in 10^{15} is achieved for arbitrary real values of the momentum transfer.Comment: 11 pages, LaTeX. The complete paper is also available via the www at http://www-ttp.physik.uni-karlsruhe.de/Preprints/ and the program can be downloaded from http://www-ttp.physik.uni-karlsruhe.de/Progdata