A MEASUREMENT OF CHARGED-PARTICLE MULTIPLICITY IN Z(O)-]C(C)OVER-BAR AND Z(O)-]B(B)OVER-BAR 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 Z(0) --> u ($) over bar u, d ($) over bar d, s ($) over bar s, Z(0) --> c ($) over bar c and Z(0) --> b ($) over bar b events of($) over bar n(uds) = 10.41 +/- 0.06 +/- 0.09 +/- 0.19; ($) over bar n(c) = 10.76 +/- 0.20 +/- 0.14 +/- 0.19; ($) over bar n(b) = 11.81 +/- 0.01 +/- 0.12 +/- 0.21where the first errors are statistical, the second systematic 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 bedelta(cl) = 0.69 +/- 0.51 +/- 0.35; delta(bl) = 2.79 +/- 0.12 +/- 0.27.These results are compared to the predictions of various models and QCD based calculations.