Measurement of the running b-quark mass using e(+)e(-) -> b(b)over-barg events

We have studied the determination of the running b-quark mass, m(b)(M-z), u sing Z(0) decays into 3 or more hadronic jets. We calculated the ratio of g reater than or equal to 3-jet fractions in e(+)e(-)--> b (b) over bar versu s e(+)e(-) --> q(i)(q) over bar(i) (q(i) = u or d or s) events at next-to-l eading order in perturbative QCD using six different infra-red- and colline ar-safe jet-finding algorithms. We compared with corresponding measurements from the SLD Collaboration and found a significant algorithm-dependence of the fitted m(b)(M-z) value. Our best estimate, taking correlations into ac count, is m(b)(M-z) = 2.56 +/- 0.27 (stat.)(-0.38)(+0.28) (syst.)(-1.48)(+0 .49) (theor.) GeV/c(2). (C) 1999 Published by Elsevier Science B.V. All rig hts reserved.