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

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 image and image 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 1015 is achieved for arbitrary real values of the momentum transfer.