2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49498The calculation of the quartic mass terms at order α_s^3 to the hadronic R ratio is described. It is based on the operator product expansion for the quark current correlator, combined with an application of the renormalization group equation.Latex, 3+2 pages, 10 ps-files included. Talk presented by R.H. at the International Europhysics Conference on High Energy Physics (EPS-HEP99), Tampere, Finland, July 15-21, 1999. The paper, with figures, is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-42/ or via www at http://www-ttp.physik.uni-karlsruhe.de/Preprints/High Energy Physics - Phenomenologytext