Studies of charged particle multiplicity in b quark events

Using the distance from the average primary vertex to reconstructed secondary vertices in jets, samples of events withb purity varying from about 13% to 89% have been selected. The charged particle multiplicity in the hemispheres opposite those containing these jets has been studied as a function of theb purity of the events. Extrapolating to 0% and 100%b purity, values of the hemisphere charged particle multiplicity inZ0? $$b\bar b$$ events and in non- $$b\bar b$$ events have been measured to be $$\begin{gathered} \bar n_b = 11.71 \pm 0.03 \pm 0.18 \pm 0.21, \hfill \\ \bar n_{udsc} = 10.32 \pm 0.01 \pm 0.07 \pm 0.19. \hfill \\ \end{gathered}$$ The first error is statistical, the second systematic and the third is a common systematic error.