Measurement of the charged multiplicity of bottom and light quark events in e+e− annihilation at GeV

Abstract The charged-particle multiplicity is measured for b -quark and light-quark ( u , d , s ) events in e + e − annihilation at s =58 GeV. Two independent methods, lepton tagging and decay-length tagging, are applied to enrich b -quark events. These methods provide event samples having different concentrations of b -quark events. The mean charged multiplicity is measured to be 19.38±0.27±0.84 for b -quark events, and 15.91±0.04±0.70 for light-quark events. The results are compared with predictions of phenomenological and theoretical models.