https://doi.org/10.1140/epjc/s10052-011-1557-x
Regular Article - Experimental Physics
A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole
1
Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011-3160, USA
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Physics Department, Universiteit Antwerpen, Universiteitsplein 1, 2610, Antwerpen, Belgium
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IIHE, ULB-VUB, Pleinlaan 2, 1050, Brussels, Belgium
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Physics Laboratory, University of Athens, Solonos Str. 104, 10680, Athens, Greece
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Department of Physics, University of Bergen, Allégaten 55, 5007, Bergen, Norway
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Dipartimento di Fisica, Università di Bologna and INFN, Viale C. Berti Pichat 6/2, 40127, Bologna, Italy
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Centro Brasileiro de Pesquisas Físicas, rua Xavier Sigaud 150, 22290, Rio de Janeiro, Brazil
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Inst. de Física, Univ. Estadual do Rio de Janeiro, rua São Francisco Xavier 524, Rio de Janeiro, Brazil
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Collège de France, Lab. de Physique Corpusculaire, IN2P3-CNRS, 75231, Paris Cedex 05, France
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CERN, 1211, Geneva 23, Switzerland
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Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, IN2P3-CNRS, BP28, 67037, Strasbourg Cedex 2, France
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Institute of Nuclear Physics, N.C.S.R. Demokritos, P.O. Box 60228, 15310, Athens, Greece
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FZU, Inst. of Phys. of the C.A.S. High Energy Physics Division, Na Slovance 2, 182 21, Praha 8, Czech Republic
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Dipartimento di Fisica, Università di Genova and INFN, Via Dodecaneso 33, 16146, Genova, Italy
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Institut des Sciences Nucléaires, IN2P3-CNRS, Université de Grenoble 1, 38026, Grenoble Cedex, France
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Helsinki Institute of Physics and Department of Physical Sciences, P.O. Box 64, 00014, University of Helsinki, Finland
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Joint Institute for Nuclear Research, Dubna, Head Post Office, P.O. Box 79, 101 000, Moscow, Russian Federation
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Institut für Experimentelle Kernphysik, Universität Karlsruhe, Postfach 6980, 76128, Karlsruhe, Germany
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Institute of Nuclear Physics PAN, Ul. Radzikowskiego 152, 31142, Krakow, Poland
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Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, 30055, Krakow, Poland
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LAL, Univ Paris-Sud, CNRS/IN2P3, Orsay, France
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School of Physics and Chemistry, University of Lancaster, Lancaster, LA1 4YB, UK
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LIP, IST, FCUL, Av. Elias Garcia, 14-1°, 1000, Lisboa Codex, Portugal
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Department of Physics, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX, UK
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Dept. of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, G12 8QQ, UK
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LPNHE, Univ. Pierre et Marie Curie, Univ. Paris Diderot, CNRS/IN2P3, 4 pl. Jussieu, 75252, Paris Cedex 05, France
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Department of Physics, University of Lund, Sölvegatan 14, 223 63, Lund, Sweden
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IPNL, IN2P3-CNRS, Université Claude Bernard de Lyon, 69622, Villeurbanne Cedex, France
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Dipartimento di Fisica, Università di Milano and INFN-MILANO, Via Celoria 16, 20133, Milan, Italy
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Dipartimento di Fisica, Univ. di Milano-Bicocca and INFN-MILANO, Piazza della Scienza 3, 20126, Milan, Italy
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IPNP of MFF, Charles Univ., Areal MFF, V Holesovickach 2, 180 00, Praha 8, Czech Republic
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NIKHEF, Postbus 41882, 1009 DB, Amsterdam, The Netherlands
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Physics Department, National Technical University, Zografou Campus, 15773, Athens, Greece
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Physics Department, University of Oslo, Blindern, 0316, Oslo, Norway
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Dpto. Fisica, Univ. Oviedo, Avda. Calvo Sotelo s/n, 33007, Oviedo, Spain
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Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK
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Dipartimento di Fisica, Università di Padova and INFN, Via Marzolo 8, 35131, Padua, Italy
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Rutherford Appleton Laboratory, Chilton, Didcot, OX11 OQX, UK
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Dipartimento di Fisica, Università di Roma II and INFN, Tor Vergata, 00173, Rome, Italy
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Dipartimento di Fisica, Università di Roma III and INFN, Via della Vasca Navale 84, 00146, Rome, Italy
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DAPNIA/Service de Physique des Particules, CEA-Saclay, 91191, Gif-sur-Yvette Cedex, France
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Instituto de Fisica de Cantabria (CSIC-UC), Avda. los Castros s/n, 39006, Santander, Spain
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Inst. for High Energy Physics, Serpukov P.O. Box 35, Protvino, Moscow Region, Russian Federation
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J. Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
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Laboratory for Astroparticle Physics, University of Nova Gorica, Kostanjeviska 16a, 5000, Nova Gorica, Slovenia
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Department of Physics, University of Ljubljana, 1000, Ljubljana, Slovenia
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Fysikum, Stockholm University, Box 6730, 113 85, Stockholm, Sweden
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Dipartimento di Fisica Sperimentale, Università di Torino and INFN, Via P. Giuria 1, 10125, Turin, Italy
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INFN, Sezione di Torino and Dipartimento di Fisica Teorica, Università di Torino, Via Giuria 1, 10125, Turin, Italy
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Dipartimento di Fisica, Università di Trieste and INFN, Via A. Valerio 2, 34127, Trieste, Italy
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Istituto di Fisica, Università di Udine and INFN, 33100, Udine, Italy
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Univ. Federal do Rio de Janeiro, C.P. 68528 Cidade Univ., Ilha do Fundão, 21945-970, Rio de Janeiro, Brazil
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Department of Radiation Sciences, University of Uppsala, P.O. Box 535, 751 21, Uppsala, Sweden
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IFIC, Valencia-CSIC, and D.F.A.M.N., U. de Valencia, Avda. Dr. Moliner 50, 46100, Burjassot, Valencia, Spain
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Institut für Hochenergiephysik, Österr. Akad. d. Wissensch., Nikolsdorfergasse 18, 1050, Vienna, Austria
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Inst. Nuclear Studies and University of Warsaw, Ul. Hoza 69, 00681, Warsaw, Poland
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Fachbereich Physik, University of Wuppertal, Postfach 100 127, 42097, Wuppertal, Germany
* e-mail: timmerma@mail.cern.ch
Received:
7
January
2011
Revised:
7
January
2011
Published online:
23
February
2011
The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, . The average value of
is measured to be 0.699±0.011. The resulting
distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data:
with a correlation factor ρ=92.2%.
Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of is found to be 0.7092±0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained:
with a correlation factor ρ=92.6%.
© Springer-Verlag / Società Italiana di Fisica, 2011