https://doi.org/10.1140/epjc/s10052-006-0017-5
Experimental Physics
Test of colour reconnection models using three-jet events in hadronic Z decays
1
Physikalisches Institut, RWTH-Aachen, 52056, Aachen, Germany
2
Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, 74019, Annecy-le-Vieux Cedex, France
3
Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona, 08193, Bellaterra (Barcelona), Spain
4
Dipartimento di Fisica, INFN Sezione di Bari, 70126, Bari, Italy
5
Institute of High Energy Physics, Academia Sinica, Beijing, P.R. China
6
European Laboratory for Particle Physics (CERN), 1211, Geneva 23, Switzerland
7
Laboratoire de Physique Corpusculaire, Université Blaise Pascal, IN2P3-CNRS, Clermont-Ferrand, 63177, Aubière, France
8
Niels Bohr Institute, 2100, Copenhagen, Denmark
9
Nuclear Research Center Demokritos (NRCD), 15310, Attiki, Greece
10
Laoratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, 91128, Palaiseau Cedex, France
11
Dipartimento di Fisica, Università di Firenze, INFN Sezione di Firenze, 50125, Firenze, Italy
12
Laboratori Nazionali dell’INFN (LNF-INFN), 00044, Frascati, Italy
13
Department of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
14
Utah Valley State College, 84058, Orem, USA
15
Kirchhoff-Institut für Physik, Universität Heidelberg, 69120, Heidelberg, Germany
16
Department of Physics, Imperial College, SW7 2BZ, London, UK
17
Institut für Experimentalphysik, Universität Innsbruck, 6020, Innsbruck, Austria
18
Department of Physics, University of Lancaster, LA1 4YB, Lancaster, UK
19
Institut de Physique Nucléaire, Département de Physique, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
20
Institut für Physik, Universität Mainz, 55099, Mainz, Germany
21
Centre de Physique des Particules de Marseille, Univ. Méditerranée, IN2P3-CNRS, 13288, Marseille, France
22
Dipartimento di Fisica, Università di Milano e INFN Sezione di Milano, 20133, Milano, Italy
23
Werner-Heisenberg-Institut, Max-Planck-Institut für Physik, 80805, München, Germany
24
Laboratoire de l’Accélérateur Linéaire, Université de Paris-Sud, IN2P3-CNRS, 91898, Orsay Cedex, France
25
Dipartimento di Fisica dell’Università, INFN Sezione di Pisa, e Scuola Normale Superiore, 56010, Pisa, Italy
26
Department of Physics, Royal Holloway & Bedford New College, University of London, TW20 OEX, Egham, Surrey, UK
27
Particle Physics Dept., Rutherford Appleton Laboratory, OX11 OQX, Chilton, Didcot, Oxon, UK
28
DAPNIA/Service de Physique des Particules, CEA, CE-Saclay, 91191, Gif-sur-Yvette Cedex, France
29
Institute for Particle Physics, University of California at Santa Cruz, 95064, Santa Cruz, CA, USA
30
Department of Physics, University of Sheffield, S3 7RH, Sheffield, UK
31
Fachbereich Physik, Universität Siegen, 57068, Siegen, Germany
32
Dipartimento di Fisica, Università di Trieste e INFN Sezione di Trieste, 34127, Trieste, Italy
33
Experimental Elementary Particle Physics, University of Washington, 98195, Seattle, WA, USA
34
Department of Physics, University of Wisconsin, 53706, Madison, WI, USA
35
Institute for Particle Physics, ETH Hönggerberg, 8093, Zürich, Switzerland
Received:
25
April
2006
Revised:
20
June
2006
Published online:
24
October
2006
Hadronic Z decays into three jets are used to test QCD models of colour reconnection (CR). A sensitive quantity is the rate of gluon jets with a gap in the particle rapidity distribution and zero jet charge. Gluon jets are identified by either energy-ordering or by tagging two b-jets. The rates predicted by two string-based tunable CR models, one implemented in JETSET (the GAL model), the other in ARIADNE, are too high and disfavoured by the data, whereas the rates from the corresponding non-CR standard versions of these generators are too low. The data can be described by the GAL model assuming a small value for the R0 parameter in the range 0.01-0.02.
Key words: Parton Shower / Time Projection Chamber / Opal Collaboration / Aleph Collaboration / Colour Reconnection
© Springer-Verlag Berlin Heidelberg 2006