Charged particle multiplicity in three-jet events and two-gluon systems
Collaboration
37 pages
Published in:
- Eur.Phys.J.C 44 (2005) 311-331
e-Print:
- hep-ex/0510025 [hep-ex]
Report number:
- CERN-PH-EP-2005-019
Experiments:
Citations per year
Abstract:
The charged particle multiplicity in hadronic three-jet events from Z decays is investigated. The topology dependence of the event multiplicity is found to be well described by a modified leading logarithmic prediction. A parameter fit of the prediction to the data yields a measurement of the colour factor ratio C_A/C_F with the result C_A/C_F = 2.261 +/- 0.014 (stat.) +/- 0.036 (exp.) +/- 0.066 (theo.) in agreement with the SU(3) expectation of QCD. The quark-related contribution to the event multiplicity is subtracted from the three-jet event multiplicity resulting in a measurement of the multiplicity of two-gluon colour-singlet states over a wide energy range. The ratios r=N_{gg}(s)/N_{q qbar}(s) of the gluon and quark multiplicities and r^{(1)}=N_{gg}'(s)/N_{q qbar}'(s) of their derivatives are compared with perturbative calculations. While a good agreement between calculations and data is observed for r^{(1)}, larger deviations are found for r indicating that non-perturbative effects are more important for r than for r^{(1)}.Note:
- 37 pages, 14 figures, Accepted by Eur. Phys. J. C Report-no: CERN-EP-PH/2005-019 Journal-ref: Eur. Phys. J. C44 (2005) 311-331 DOI: 10.1140/epjc/s2005-02390-x
- electron positron: colliding beams
- electron positron: annihilation
- Z0: electroproduction
- Z0: hadronic decay
- final state: (3jet)
- quark: jet
- gluon: jet
- event shape analysis
- charged particle: multiplicity
- leading logarithm approximation
References(67)
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