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Title: Determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale dependence of multiplicity in three jet events

Abstract

I examine the determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale evolution of particle multiplicity in e{sup +}e{sup -} three jet events. I fit an analytic expression for the multiplicity in three jet events to event samples generated with QCD multihadronic event generators. I demonstrate that a one parameter fit of C{sub A}/C{sub F} yields the expected result C{sub A}/C{sub F}=2.25 in the limit of asymptotically large energies if energy conservation is included in the calculation. In contrast, a two parameter fit of C{sub A}/C{sub F} and a constant offset to the gluon jet multiplicity, proposed in a recent study, does not yield C{sub A}/C{sub F}=2.25 in this limit. I apply the one parameter fit method to recently published data of the DELPHI experiment at the e{sup +}e{sup -} collider LEP at CERN and determine the effective value of C{sub A}/C{sub F} from this technique, at the finite energy of the Z{sup 0} boson, to be 1.74{+-}0.03{+-}0.10, where the first uncertainty is statistical and the second is systematic. (c) 2000 The American Physical Society.

Authors:
 [1]
  1. Department of Physics, University of California, Riverside, California 92521 (United States)
Publication Date:
OSTI Identifier:
20216465
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 61; Journal Issue: 11; Other Information: PBD: 1 Jun 2000; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; QUANTUM CHROMODYNAMICS; COLOR MODEL; JET MODEL; MONTE CARLO METHOD; ELECTRON-POSITRON INTERACTIONS; QUARKS; GLUONS; EXPERIMENTAL DATA; THEORETICAL DATA

Citation Formats

Gary, J. William. Determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale dependence of multiplicity in three jet events. United States: N. p., 2000. Web. doi:10.1103/PhysRevD.61.114007.
Gary, J. William. Determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale dependence of multiplicity in three jet events. United States. doi:10.1103/PhysRevD.61.114007.
Gary, J. William. Thu . "Determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale dependence of multiplicity in three jet events". United States. doi:10.1103/PhysRevD.61.114007.
@article{osti_20216465,
title = {Determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale dependence of multiplicity in three jet events},
author = {Gary, J. William},
abstractNote = {I examine the determination of the QCD color factor ratio C{sub A}/C{sub F} from the scale evolution of particle multiplicity in e{sup +}e{sup -} three jet events. I fit an analytic expression for the multiplicity in three jet events to event samples generated with QCD multihadronic event generators. I demonstrate that a one parameter fit of C{sub A}/C{sub F} yields the expected result C{sub A}/C{sub F}=2.25 in the limit of asymptotically large energies if energy conservation is included in the calculation. In contrast, a two parameter fit of C{sub A}/C{sub F} and a constant offset to the gluon jet multiplicity, proposed in a recent study, does not yield C{sub A}/C{sub F}=2.25 in this limit. I apply the one parameter fit method to recently published data of the DELPHI experiment at the e{sup +}e{sup -} collider LEP at CERN and determine the effective value of C{sub A}/C{sub F} from this technique, at the finite energy of the Z{sup 0} boson, to be 1.74{+-}0.03{+-}0.10, where the first uncertainty is statistical and the second is systematic. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevD.61.114007},
journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 11,
volume = 61,
place = {United States},
year = {2000},
month = {6}
}