A test of the flavor independence of αs at the Z0 resonance

We compare the ratio of the strong coupling αs measured in Z0 → b bar b events to that measured in Z0 → q bar q(q=u,d,s,c) in the SLD experiment at SLAC. Z0 → b bar b events are identified with the aid of a precision silicon vertex detector by requiring that at least three charged tracks pass more than 3.0σ from the Z0 decay vertex. This method has an estimated efficiency of 54% with a purity of 71%. Jets are identified and counted by clustering charged tracks according to the JADE algorithm. By comparing the 3-jet fraction in tagged events to that in all hadronic events, we extract a preliminary result of αs(b)/αs(udsc) = 1.18 ± 0.11(stat) ± 0.05(sys)