Elsevier

Physics Letters B

Volume 550, Issues 1–2, 12 December 2002, Pages 33-46
Physics Letters B

Charged particle multiplicities in heavy and light quark initiated events above the Z0 peak

https://doi.org/10.1016/S0370-2693(02)02935-0Get rights and content
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Abstract

We have measured the mean charged particle multiplicities separately for bb̄, cc̄ and light quark (uū,dd̄,ss̄) initiated events produced in e+e annihilations at LEP. The data were recorded with the OPAL detector at eleven different energies above the Z0 peak, corresponding to the full statistics collected at LEP1.5 and LEP2.

The difference in mean charged particle multiplicities for bb̄ and light quark events, δbl, measured over this energy range is consistent with an energy independent behaviour, as predicted by QCD, but is inconsistent with the prediction of a more phenomenological approach which assumes that the multiplicity accompanying the decay of a heavy quark is independent of the quark mass itself. Our results, which can be combined into the single measurement δbl=3.44±0.40(stat)±0.89(syst) at a luminosity weighted average centre-of-mass energy of 195 GeV, are also consistent with an energy independent behaviour as extrapolated from lower energy data.

Cited by (0)

1

And at TRIUMF, Vancouver, V6T 2A3 Canada.

16

Now at Physics Department, Southern Methodist University, Dallas, TX 75275, USA.

2

And Royal Society University Research Fellow.

7

And Research Institute for Particle and Nuclear Physics, Budapest, Hungary.

19

Now at Universitaire Instelling Antwerpen, Physics Department, B-2610 Antwerpen, Belgium.

3

And Institute of Nuclear Research, Debrecen, Hungary.

20

Now at RWTH Aachen, Germany.

12

Now at University of Toronto, Deptartment of Physics, Toronto, Canada.

15

Now at University of California, San Diego, USA.

9

And CERN, EP Div., 1211 Geneva 23.

13

Current address: Bergische Universität, Wuppertal, Germany.

14

And University of Mining and Metallurgy, Cracow, Poland.

18

Now at IEKP Universität Karlsruhe, Germany.

10

Now at University of Nijmegen, HEFIN, NL-6525 ED Nijmegen, The Netherlands, on NWO/NATO Fellowship B 64-29.

6

And MPI München.

8

Now at University of Liverpool, Department of Physics, Liverpool L69 3BX, UK.

4

And Heisenberg Fellow.

5

And Department of Experimental Physics, Lajos Kossuth University, Debrecen, Hungary.

17

Now at IPHE Université de Lausanne, CH-1015 Lausanne, Switzerland.

11

Now at University of Kansas, Department of Physics and Astronomy, Lawrence, KS 66045, USA.