par Abreu, Pedro;Bertrand, Daniel 
;Herquet, Philippe ;Huet, Kathy ;Lefebure, Véronique ;Wickens, John H. ; [et al.]
Référence Physics letters. Section B, 479, 1-3, page (118-218)
Publication Publié, 2000-04-20
;Herquet, Philippe ;Huet, Kathy ;Lefebure, Véronique ;Wickens, John H. ; [et al.]Référence Physics letters. Section B, 479, 1-3, page (118-218)
Publication Publié, 2000-04-20
Article révisé par les pairs
| Résumé : | 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- → bb̄ events, [removed](bb̄), and the difference δ(bl) between [removed](bb̄) and the multiplicity, [removed](ll̄), in genetic light quark (u,d,s) events: δ(bl)(183 GeV) = 4.55 ± 1.31(stat) ± 0.73(syst), δ(bl)(189 GeV) = 4.43 ± 0.85(stat) ± 0.61(syst), δ(bl)(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. |
