Three-loop nonsinglet matching coefficients for heavy quark currents

We compute the matching coefficients between QCD and nonrelativistic QCD for external vector, axial-vector, scalar, and pseudoscalar currents up to three-loop order. We concentrate on the nonsinglet contributions and present precise numerical results with an accuracy of about ten digits. For the vector current the results from Marquard et al. [Phys. Rev. D 89, 034027 (2014)] are confirmed, increasing the accuracy by several orders of magnitude