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Mini-Jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions

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Mini-Jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions SE9700141 Mini-Jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions Haiqiao Wang Department of Cosmic and Subatomic Physics CO University of Lund i LUND 1997 Organization Documant nama LUND UNIVERSITY DOCTORAL DISSERTATION Cosmic and Subatomic Physiscs Data of iuua Univeristy of Lund March 1997 Box 118 CODEN: S-221 00 LUND, Sweden ISRN LUNFD6/NFFK-1013-SE+124P Author)*) Sponsoring organization Haiqiao Wang Tit*.mi.uMiti. Mini.jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions Abstract The thesis is based on the data analysis and detector development of the EMU01 / CERN, E863 / BNL andUAl /CERN experiments. Particle fluctuations are studied with the scaled factorial moments in the fragmentation region of oxygen - induced emulsion interactions from 3.7 to 200 A GeV. The intermittency indices show an energy independent behaviour in the target and projectile regions of pseudorapidity. In order to study the origin of the fluctuations, jet - like and ring - like substructures of panicles produced in the azimuthal plane are investigated for the S - Au, S-Em and O-Em interactions at 200 A GeV. The study shows that the two - particle azimuthal correlations can be well understood if Bose - Einstein correlations and Y - conversion are included. A nuclear rescattenng model, which incorperates the FRITIOF model, has been developed. The model can well describe multiplicity distributions of slow recoiling protons, evaporation particles and a their correlations with particles produced in high energy heavy - ion collisions. In the autumn of 1994, truly heavy nuclei (Pb) were accelerated to 158 A GeV A: at the CERN / SPS. In o order to improve the measurements of Pb - induced collisions, an automatic system based on the CCD technique and image processing was developed. This system has been used to measure densities of the particles produced. h Mini - jet production is studied using the UA1 1987 minimum bias data sample for p bar p interaction at s = 630 GeV. The study shows that the transverse energy distribution of mini - jets is in good agreement with the QCD prediction. The angular distributions of two leading jets show the behaviour of elastic scattering of partons with gluon exchange. §1 Keyword! proton antiproton interaction, heavy ion collision, quark-gluon plasma, dynamical fluctuation, intermittency, limiting fragmentation, target fragmentation, intranuclear cascade, image processing, mini-jet Classification system and/or index Mrmt (if any) Supplementary bibliographical Information Language English ISSN and toy tltM ISBN ISSN 1101-4202 Cosmic and Subatomic Physics Dissertation 91-628-2375-2 Recipient's not** Numbar of pages Prlca 124 Sacurtty claaslf Icstlon Diatrlbution by (nama and address) Haiqiao Wang, Cosmic and Subatomic Physiscs Box 118, S-221 00 LUND, Sweden I, the undersigned, being the copyright owner of the abstract of the above-mentioned dissertation, hereby grant to all reference sources permission to publish and disseminate the abstract of the above-mentioned dissertation. Signature Date March 18. 1997 Mini-Jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions by Haiqiao Wang Thesis for the degree of Doctor of Philosophy Lund April 1997 COSMIC AND SUBATOMIC PHYSICS DISSERTATION ISSN 1101-4202 ISRN LUNFD6/NFFK-1013-SE+124P ISBN 91-628-2375-2 University of Lund Institute of Physics Box 118 S-221 00 Lund Sweden By Haiqiao Wang Printed by KFS AB in Sweden Lund 1997 The papers are reprinted in the thesis with the permission of the copy- right holders. Paper I,III : Springer-Verlag, Journal production department III, Postfach 105280, D-69042, Heidelberg, Germany Paper II: Institute of physics publishing, Techno house, Reacliffe way, Bristol BS1 6NX U.K. The cooperation of the copyright holders is gratefully acknowledged. To my wife Ronghui and my daughter Yafei NEXTPAQE(S) toft BLANK Preface This thesis deals with mini-jet production in proton-antiproton collisions at •y/s = 630 GeV, particle production and nuclear fragmentation in high energy heavy-ion interactions. The results shown in the thesis are based on the experi- ments EMU01/CERN, E863/BNL and UA1/CERN. The thesis is organized in the following way. Chapter 1 gives an introduction to the field of high energy heavy-ion physics. The EMU01/CERN and E863/BNL experiments are described in Chapter 2. The details of a new automatic measuring system based on the CCD technique and image processing are also given in this chapter. Chapter 3 describes the mini-jet production in pp interactions at -^/s=630 GeV. The papers involved in this thesis are summarized in Chapter 4. The thesis includes the following five papers. 1) M. I. Adamovich et. al. (EMU01 Collaboration), A systematic study of the energy independent behaviour of the fragmentation regions in 160-Em interactions from 3.7 to 200 A GeV. Z. Phys. C55 (1992) 509. 2) M. I. Adamovich et al. (EMU01 Collaboration), On the jet-like and ring-like substructure in distributions of produced particles in central heavy-ion interactions at ultra-relativistic energies. J. Phys. G: Nucl. Part. Phys. 19 (1993) 2035. 3) M. I. Adamovich et al. (EMU01 Collaboration), On the production of slow particles in high energy heavy-ion collisions. Z. Phys. C65 (1995) 421. 4) A. Norton et al. (UA1 MIMI Collaboration), Production of mini-jets in pp collision at ^=630 GeV. Helsinki University, Physics Report (1997). 5) H. Q. Wang et al., A CCD-based automatic system for tracking charged particles in high energy heavy-ion collisions. To be submitted to Nucl. Instr. and Meth. (1997). During my Ph.D study I had the opportunity to attend the following interna- tional conferences and presented my work: 1) European Research Conference on Physics of High Energy Heavy-Ion Col- lisions, Vuosaari, Finland, June 17-22, 1994. 2) The International Nuclear Physics Conference-INPC'95, Beijing, China, August 21-26, 1995. 3) Twelfth International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter'96), Heidelberg, Germany, May 21-25, 1996. Abstract The thesis is based on the data analysis and detector development of the EMU01/CERN, E863/BNL and UA1/CERN experiments. Particle fluctuations are studied with the scaled factorial moments in the fragmentation region of 16O-induced emulsion interactions from 3.7 to 200 A GeV. The intermittency indices show an energy independent be- haviour in the target and projectile regions of pseudorapidity. In order to study the origin of the fluctuations, jet-like and ring-like substructures of particles produced in the azimuthal plane are investigated for the 32S-Au, 32S-Em and 160-Em interactions at 200 A GeV. The study shows that the two-particle azimuthal correlations can be well understood if Bose- Einstein correlations and 7-conversion are included. A nuclear rescattering model, which incorperates the FRITIOF model, has been developed. The model can well describe multiplicity distributions of slow recoiling protons, evaporation particles and their correlations with particles produced in high energy heavy-ion collisions. In the autumn of 1994, truly heavy nuclei (Pb) were accelerated to 158 A GeV/c at the CERN/SPS. In order to improve the measurements of Pb- induced collisions, an automatic system based on the CCD technique and image processing was developed. This system has been used to measure densities of the particles produced. Mini-jet production is studied using the UAl 1987 minimum bias data sample for pp interaction at v^s=630 GeV. The study shows that the ET distribution of mini-jets is in good agreement with the QCD prediction. The angular distributions of two leading jets show the behaviour of elastic scattering of partons with gluon exchange. Acknowledgments I would like to express my gratitude to ... My senior supervisor, Professor Ingvar Otterlund, who gave me the chance to study toward Ph.D in experimental nuclear physics at the Physics Department, Lund University, for his enthusiastic support and great patience during my study. Senior Dr. Alan R. Norton, for his strong financial support and all the good physics ideas he presented to me. Without his support it would have been im- possible for me to stay at CERN from Feburary to August 1993 and to study the mini-jet production in the minimum bias trigger events collected by the UA1 detector. Dr. Evert Stenlund, who has given me a lot of valuable help both in discussions on physics and on daily life, and most especially the great help he gave me at the begining of my stay in Lund. Professor Jorma Tuominiemi, for the discussions and encourgement concerning the mini-jet analysis. My colleagues Drs. Bo Jakobsson, Sten Garpman and Kaj Soderstrom for all their help and advice. I also would like to thank ... My Ph.D fellows Anders Eklund, Joakim Nystrand, Karim El Chenawi and Tom Svensson. Mrs. Visnja Kopljar and Mr. Johan Martensson. Finally the financial support from Naturvetenskapliga Forskningsrddei, Kung- liga Fysiografiska Sailskapet i Lund and Knut och Alice Wallenbergs stiftelse is gratefully acknowledged. NEXTPAQE(S) left BLANK Contents Chapter 1 Introduction 13 1.1 The building blocks of matter 13 1.2 Physics motivation for high energy heavy-ion research 14 1.2.1 History of experimental high energy heavy-ion research . 16 1.2.2 History of theoretical high energy heavy-ion research .... 17 1.3 Particle production and nuclear stopping power 19 1.4 The spectator-participant picture 19 1.5 Some observables in
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