Testing the QCD Lagrangian by measuring the b quark mass at high energies

Theoretical calculations at next-to-leading order (NLO) in QCD perturbation theory allow for improved experimental tests of QCD. Flavour independence of alpha /sub s/ has been verified with high precision by the DELPHI, SLD, ALEPH and OPAL collaborations, taking as an input the b-quark mass extracted from independent measurements done at low scales. Assuming alpha /sub s/ universality, three compatible measurements of the running b-quark mass, m/sub b/(M/sub Z /), defined in the MS scheme at the M/sub Z/ scale, have been performed with DELPHI, SLD and ALEPH data. (19 refs).