Analytic Continuation of the Harmonic Sums for the 3--Loop Anomalous Dimensions

Abstract

We present for numerical use the analytic continuations to complex arguments of those basic Mellin transforms, which build the harmonic sums contributing to the 3--loop anomalous dimensions. Eight new basic functions contribute in addition to the analytic continuations for the 2--loop massless Wilson coefficients calculated previously. The representations derived have a relative accuracy of better than $10^{-7}$ in the range $x \epsilon [10^{-6},0.98]$.