Abstract
Gluon jets with about 39 GeV energy are identified in hadronic Z0 decays by tagging two jets in the same hemisphere of an event as quark jets. Identifying the gluon jet to be all the particles observed in the hemisphere opposite to that containing the two tagged jets yields an inclusive gluon jet definition corresponding to that used in analytic calculations, allowing the first direct test of those calculations. In particular, this jet definition yields results which are only weakly dependent on a jet finding algorithm. We find rch. = 1.552 ± 0.041 (stat.) ± 0.061 (syst.) for the ratio of the mean charged particle multiplicity in gluon jets to that in light quark uds jets, where the uds jets are identified using an inclusive jet definition similar to that used for the gluon jets. Our result is in general agreement with the prediction of a recent analytic calculation which incorporates energy conservation into the parton shower branching processes, but is considerably smaller than analytic predictions which do not incorporate energy conservation.
Original language | English |
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Pages (from-to) | 659-672 |
Number of pages | 14 |
Journal | Physics Letters B |
Volume | 388 |
Issue number | 3 |
DOIs | |
State | Published - Nov 21 1996 |
Externally published | Yes |
Funding
We particularly wish to thank the SL Division for the efficient operation of the LEP acceleratora nd for their continuing close cooperation with our experimental group. In addition to the support staff at our own institutions we are pleasedt o acknowledget he Departmento f Energy, USA, National Science Foundation, USA, Particle Physics and Astronomy Research Council, UK Natural Sciences and Engineering Research Council, Canada, Israel Ministry of Science, Israel Science Foundation, administeredb y the Israel Academy of Science and Humanities, Minerva Gesellschaft, Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program, German Israeli Bi-national Science Foundation (GIF), Direction des Sciences de la Matiere du Commissariat a 1’Energie Atomique, France, Bundesministerium fiir Bildung, Wissenschaft, Forschung und Technologie, Germany, National Research Council of Canada, Hungarian Foundation for Scientific Research,O TKA T-016660, and OTKA F-015089.