P. Abreu et al., CHARGED-PARTICLE MULTIPLICITY IN E(-)-]Q(Q)OVER-BAR EVENTS AT 161 AND172 GEV AND FROM THE DECAY OF THE W-BOSON()E(), Physics letters. Section B, 416(1-2), 1998, pp. 233-246
The data collected by DELPHI in 1996 have been used to measure the ave
rage charged particle multiplicities and dispersions in q (q) over bar
events at centre-of-mass energies of root s = 161 GeV and root s = 17
2 GeV, and the average charge multiplicity in WW events at root s = 17
2 GeV. The multiplicities in q (q) over bar events are consistent with
the evolution predicted by QCD. The dispersions in the multiplicity d
istributions are consistent with Koba-Nielsen-Olesen (KNO) scaling. Th
e average multiplicity of charged particles in hadronic W decays has b
een measured for the first time; its value, 19.23 +/- 0.74(stat + syst
), is consistent with that expected for an e(+)e(-) interaction at a c
entre-of-mass energy equal to the W mass. The charged particle multipl
icity in W decays shows no evidence of effects of colour reconnection
between partons from different W's at the present level of statistics.
(C) 1998 Elsevier Science B.V.