ADEVA, B (reprint author), CERN,EUROPEAN LAB PARTICLE PHYS,CH-1211 GENEVA 23,SWITZERLAND.
We have measured the ratio of the strong coupling constants alpha(s) for bottom quarks and light quarks at the Z0 resonance, in order to test the flavour independence of the strong interaction. The coupling strength alpha(s) has been determined from the fraction of events with three jets, measured for a sample of all hadronic events, and for inclusive muon and electron events. The b purity is evaluated to be 22% for the first data set and 87% for the inclusive lepton sample. We find alpha(s)(b)/alpha(s)(udsc) = 1.00 +/-0.05 (stat.) +/- 0.06 (syst.).