A measurement of charged particle multiplicity in Z0 → cc̄ and Z0 → bb̄ events

We have used data from the OPAL detector at LEP to reconstruct D∗ mesons and secondary vertices in jets. We have studied the hemispheres of the events opposite these jets and obtain values of the hemisphere charged particle multiplicity in Z0 → uu, dd, ss, Z0 → cc and Z0 → bb events of nuds = 10.41 ± 0.06 ± 0.09 ± 0.19; nc = 10.76 ± 0.20 ± 0.14 ± 0.19; nb = 11.81 ± 0.01 ± 0.12 ± 0.21 where the first errors are statistical, the second systmatic and the third a common scale uncertainty. We find the difference in total charged particle multiplicity between c and b quark events and light (u, d, s) quark events to be δcl = 0.69 ± 0.51 ± 0.35; δbl = 2.79 ± 0.12 ± 0.27. These results are compared to the predictions of various models and QCD based calculations.