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Photographs included in the original manuscript have tieen reproduced xerographically in this copy. Higfier quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA UMI 800-521-0600 UNIVERSITY OF OKLAHOMA GRADUATE COLLEGE Measurement of the Angular Distribution of Electrons from W Boson Decays at D 0 A Dissertation SUBMITTED TO THE GRADUATE FACULTY In partial fulfillment of the requirements for the degree of Doctor of Philosophy by GEORG STE1NBRÜCK Norman, Oklahoma 1999 UMi Number 9949701 UMI UMI Microform9949701 Copyright 2000 by Bel! & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 © Georg Steinbrück 1999 ALL RIGHTS RESERVED Measurement of the Angular Distribution of Electrons from W Boson Decays at D 0 A Dissertation APPROVED FOR THE DEPARTMENT OF PHYSICS AND ASTRONOMY BY Pjiii^^^utierrez ^ ^xOeorge Kalbfleisch ^ Ron Kantowski / Sheena iVrarphy James Hawthorne Acknowledgments This dissertation is a cumulative effort of many years of research conducted by a large number of people. I would like to thank everyone who has contributed to this work in some fashion. First and foremost, I want to thank my advisor, Professor Phil Gutierrez, for his continuous support and interest in this analysis and in my work as a graduate student at the University of Oklahoma. His expertise and guidance were greatly appreciated as he helped to get me started on many projects that needed the initial input by someone experienced in high energy physics. At D0, I would like to thank the members of the WZQCD group under the strong leadership of Cecilia Gerber for their continuous support. Without the help of Cecilia and Miguel Mostafa, who is working on the W pr analysis, this analysis would not have been completed by now. Darien Wood deserves recognition for proposing this analysis and for answering many questions I had along the way. Next I would like to thank all teachers who have helped me to understand physics and who are paxt of the reason I am here now. In chronological order these are my two high school teachers, Herr Kruger and Herr Lameck who taught math and physics to me and were an important factor in my decision to study physics. Then I would like to mention the professors at the University of Heidelberg from whom I learned basic and advanced physics. Specially Professor zu Putlitz (experimental physics). Professor Wegner (theoretical mechanics and statistical mechanics) and Professor Freitag (functions theory) deserve recognition for their well structured and interesting lectures. I would also like to thank my friends in Heidelberg: Markus, Georg, Jorg and Burkhard. We had a lot of fun together solving physics problems and just hanging out. While the lectures in Germany were sometimes crowded and somewhat anony- IV mous, I had the opportunity to experience a very different style of teaching at the University of Oklahoma. Small classes provided the opportunity for intense interaction between students and professors. AU of the classes I took in Oklahoma were very inspiring. Thanks to Professors Jack Cohn (general relativity), Dave Kaplan (particle physics I), Ron Kantowski (quantum field theory), Phü Gutierrez (particle physics II), and Jeff Purinton (Aristotelean and Platonic philosophy). I also had the opportunity to get my first teaching experience as a teaching assistant under Professor George Kalbfleisch in a two semester electronics lab. This was an especially interesting task since I had to learn electronics while teaching it. Maybe the greatest thanks should go to my family. My wife Trish has always supported my career as a physicist with aU the difficulties it brings with it. Thanks also to my beautiful children Lili and Evi, who bring so much fun and excitement into our lives. I am very grateful to my parents for their love and support over the years. You have always supported my dreams in life! Thanks to my brothers Andreas and Christian for our good childhood memories. I would also like to thank our friends Magdalena and Tom for lots of great dinners and conversations we enjoyed together. Finally, my in-laws deserve thanks for making me part of their loving family and introducing me to the United States. To Trish, Lili and Evi VI C ontents 1 The Standard Model of High Energy Physics 1 Symmetry groups....................................................................................... 3 1.1 1.2 The particles ............................................................................................. 5 1.3 Electroweak interactions.......................................................................... 6 1.4 The Higgs Mechanism ............................................................................. 9 1.5 QCD as a gauge theory .......................................................................... 12 2 Angular Distribution Theory 19 2.1 Some Intuition into the Angular Distribution...................................... 24 3 The Experiment 27 3.1 The Fermilab Tevatron............................................................................ 27 3.2 Overview of the Whole Detector............................................................. 31 3.3 The Central Detector................................................................................ 33 3.3.1 The Vertex Chamber..................................................................... 34 3.3.2 The Transition Radiation D etector........................................... 35 3.3.3 The Central Drift Cham ber........................................................ 36 3.3.4 The Forward Drift Chambers ..................................................... 38 3.4 The Calorimeter ...................................................................................... 39 3.4.1 Calorimeter Design........................................................................ 42 3.4.2 Central Calorimeter........................................................................ 45 3.4.3 Endcap Calorimeter ..................................................................... 46 Vll
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