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SLAC-R-821 BABAR-THESIS-04/123 Rare B Meson Decays With Omega Mesons Lei Zhang Stanford Linear Accelerator Center Stanford University Stanford, CA 94309 SLAC-Report-821 Prepared for the Department of Energy under contract number DE-AC02-76SF00515 Printed in the United States of America. Available from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161. This document, and the material and data contained therein, was developed under sponsorship of the United States Government. Neither the United States nor the Department of Energy, nor the Leland Stanford Junior University, nor their employees, nor their respective contractors, subcontractors, or their employees, makes an warranty, express or implied, or assumes any liability of responsibility for accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use will not infringe privately owned rights. Mention of any product, its manufacturer, or suppliers shall not, nor is it intended to, imply approval, disapproval, or fitness of any particular use. A royalty-free, nonexclusive right to use and disseminate same of whatsoever, is expressly reserved to the United States and the University. Rare B Meson Decays with ω Mesons by Lei Zhang B.E., University of Science and Technology of China, 1996 M.S., Institute of High Energy Physics, Beijing, 1999 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Physics 2004 This thesis entitled: Rare B Meson Decays with ω Mesons written by Lei Zhang has been approved for the Department of Physics William T. Ford Prof. Thomas A. DeGrand Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. iii Zhang, Lei (Ph.D., Physics) Rare B Meson Decays with ω Mesons Thesis directed by Prof. William T. Ford Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter- antimatter asymmetry in our universe, and of their roles in testing the “effective” theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced BB pairs on the BABAR experiment, we observed the decays B0 → ωK0 and B+ → ωρ+ for the first time, made more precise measurements for B+ → ωh+ and reported tighter upper limits for B → ωK∗ and B0 → ωρ0. The branching fractions measured are B(B+ → ωπ+) = (5.5 ± 0.9 ± 0.5) × 10−6, + + −6 0 0 +1.6 −6 0 B(B → ωK ) = (4.8±0.8±0.4)×10 , B(B → ωK ) = (5.9−1.3±0.5)×10 , B(B → ∗0 +1.8 −6 −6 + ∗+ +2.5 −6 ωK ) = (3.4−1.6±0.4)×10 (< 6.0×10 ), B(B → ωK ) = (3.5−2.0±0.7)×10 (< −6 0 0 +1.3 −6 −6 + 7.4 × 10 ), B(B → ωρ ) = (0.6−1.1 ± 0.4) × 10 (< 3.3 × 10 ), and B(B → + +3.7 −6 ωρ ) = (12.6−3.3 ± 1.6) × 10 . We also measure time-integrated charge asymmetries + + + + Ach(B → ωπ ) = 0.03 ± 0.16 ± 0.01, Ach(B → ωK ) = −0.09 ± 0.17 ± 0.01, and + + + + Ach(B → ωρ ) = 0.05 ± 0.26 ± 0.02. For B → ωρ we also measure the longitudinal + + +0.12 polarization fraction fL(B → ωρ ) = 0.88−0.15 ± 0.03. To my wife Yi Sun and my daughter Cindy. Acknowledgements I am very fortunate that lots of people have helped me so much that without them I could not possibly come this far in my academic study and get this research work done. It would take quite a few pages to name all of them, and I might not be able to express my deepest appreciation to them all explicitly. Nevertheless, I owe a great deal to the people who have supported me during various times. First of all, I must gratefully acknowledge my advisor, Bill Ford, who has accepted me as Ph.D. student and given me the opportunity to undertake my research as part of the BABAR Collaboration. His enthusiasm, encouragement and endless support were always what I could rely on when things looked pessimistic. It has been a great pleasure to work him and it is hard for me to imagine that one could have a better advisor than Bill. I would also like to thank Jim Smith for his helpful advice and guidance during all the stages of this project. Discussions with him were so fruitful that I could end up with nothing otherwise when the analysis went stalled many times. Whenever it looked the hardest time to me, Jim and Bill were there to help. It is a tremendous task requiring team effort for anyone to accomplish any achieve- ment in this field, and I would like to thank Jean Roy for his early work on ωh+ analysis; Mirna van Hoek for her great analysis tools, Q2BUser and Q2BFit; Paul Bloom for his insightful discussions and initial setup on ωK∗ and ωρ analysis; Fred Blanc for his invaluable help in different stages of the analysis. Thanks also to Phil, Corry, Keith, Fabian, Ian, Josh, Ishani, and all other Colorado group members who have made it such vi a wonderful team to work with. I am also very grateful to all the BABAR collaboration members who have made this work possible and all the PEP-II staff who have provided us with excellent lumi- nosity and machine conditions. I want to thank Conveners and members from Quasi- Two-Body Charmless Analysis Working Group and many other AWGs of BABAR, for their unending support and beneficial discussions throughout the whole work and my special thanks go to Jim Olsen, Bill Ford, Adrian Bevan, Jim Smith, Erich Varnes, Luca Cavoto. I also thank Wouter Verkerke and David Kirkby for their wonderful con- tributions of RooFit packages, John Back for his helpful discussion on RooDircPdf, Alex Olivas for his help on digi-embedding studies, Andrei Gritsan and LLuisa Maria Mir for their valuable discussions on VV analysis, Shahram Rahatlou for his excellent research and thesis. Other colleagues who help me a lot and to whom I owe a lot are: Ming Chao, Jinlong Zhang, Wei Yang, Aidong Chen, Gerhard Raven, Nick Danielson, and many more. Thanks should also go to my analysis review committee members, Bob Cahn, Massimo Carpinelli, Sasha Telnov, Carlo Dallapiccola, Teela Marie Pulliam, Haibo Li, the institutional reviewers and the PubBoard members for their timely re- views, comments and final approvals. I want to thank Haibo again for being my best friend and mentor for so many years. I have spent one year at SLAC, which turned out to be a very happy experience, and I could not leave without saying thanks to Vera L¨uth, the leader of Group C which hosted me. I also need to thank the administrative and technical staff at SLAC, in particular Anna Pacheco, Nuria Ayala, Charlotte Hee, who have saved me lots of time and provided me with the best services. Life at SLAC was even more wonderful with all my friends around the Bay Area and I had lots of fun with many of them, including: Jiquan Guo (Stanford), Changjun Ma (SBC), Haiming Xu (Philips), Shunjiang Xu (SUN), Wei Zhao (Stanford), Rita Chen (SUN). My thanks to all of them and their families. vii Throughout years of study at University of Colorado at Boulder, I have constantly received enlightenment and inspiration from many faculty members from the Depart- ment of Physics and other departments and I express my gratitude to all of them and particularly to Walter Wyss, Neil Ashby, Jim Shepard, Tom DeGrand, Uriel Nauenberg, Hal Gabow, Roger King, Kenneth Anderson. I would like to thank Susan Thompson, Kathy Oliver, Joe Hurst, Mary Dang and all the staff for their excellent work. Either on campus, or around Boulder and Denver Metro area, lots of friends from many different backgrounds make everyday part of excitements. I especially thank Madam Zhen Xia for treating my daughter like her own granddaughter; Changying Li’s family for being our best friend and neighbor for almost four years. In spite of my best efforts, this work can not be done on time without generous support from my committee, Bill Ford, Jim Smith, John Cumalat, Tom DeGrand, and Yung-Cheng Lee, to whom I owe a very special debt. My acknowledgements would not be nearly complete without mentioning my fam- ily and relatives nearby or far apart. I must thank my parents for their timeless faith in me and constant support to me; and I should also thank my two sisters, who, during all the years I have been away from my parents, have showed the traditional merits of being company to my parents and making them happier. I am extremely grateful to my mother-in-law for her liberal help by taking care of my daughter many times. Lastly, and most important, I want to thank my wonderful wife. She gave up her job in Beijing, her hometown, where she never left before, to come with me for my study. She gave me perpetual love, support and encouragement that helped to bring this project to its successful completion.
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