The DELPHI detector at LEP has collected 54 pb(-1) of data at a
centre-of-mass energy around 183 GeV during 1997, 158 pb(-1) around 189
GeV during 1998, and 187 pb(-1) between 192 and 200 GeV during 1999.
These data were used to measure the average charged particle
multiplicity in e(+)e(-)->b (b) over bar events: (n)(b (b) over bar),
and the difference delta(hl) between (n)(b (b) over bar) and the
multiplicity, (n)(l (l) over bar), in generic light quark (u,d,s)
events:
delta(hl)(183 GeV) = 4.55 +/- 1.31(stat) +/- 0.73(syst),
delta(hl)(189 GeV) = 4.43 +/- 0.85(stat) +/- 0.61(syst),
delta(hl)(200 GeV) = 3.39 +/- 0.89(stat) +/- 1.01 (syst).
This result is consistent with QCD predictions, while it is inconsistent
with calculations assuming that the multiplicity accompanying the decay
of a heavy quark is independent of the: mass of the quark itself. (C)
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