The BABAR physics book physics at an asymmetric b factory

SLAC-R-504

The BABAR Physics Book:
Physics at an Asymmetric B Factory
 
This book presents the results of a year-long workshop devoted to a review of the physics
opportunities of the BABAR experiment at the PEP-II B Factory, at the Stanford Linear
Accelerator Center Laboratory.

* Work supported in part by US Department of Energy contract DE-AC02-76SF00515.
SLAC National Accelerator Laboratory, Menlo Park, CA 94025


This page was intentionally left blank.


The BABAR Collaboration
LAPP Annecy, Annecy-le-Vieux, France
D. Boutigny, I. De Bonis, Y. Karyotakis, R. Lafaye, V. Tisserand
INFN Sezione di Bari, Bari, Italy
C. Evangelista, A. Palano
Beijing Glass Research Institute, Beijing, China
G. Chen, S. Ren, O. Wen, H. Yu, F. Zhang, Y. Zheng
Institute of High Energy Physics, Beijing, China
G. Chen, Y. Guo, H. Lan, H. Mao, N. Qi, P. P. Xie, W. G. Yan, C. Zhang, W. Zhao, Y. Zhu
University of Bergen, Bergen, Norway
A. Borgland, G. Eigen, B. Stugu
Ruhr-Universit¨at Bochum, Bochum, Germany
H. Koch, M. Kunze, B. Lewandowski, K. Peters, H. Schm¨ucker, M. Steinke
University of Bristol, Bristol, UK
J. C. Andress, N. Dyce, B. Foster, A. Mass, J. McFall

University of British Columbia, Vancouver, British Columbia, Canada
C. Hearty, M. H. Kelsey, J. McKenna
Brunel University, London, UK
B. Camanzi, T. J. Champion, A. K. McKemey, J. Tinslay
Budker Institute of Nuclear Physics, Novosibirsk, Russia
V. E. Blinov, A. D. Bukin, A. R. Buzykaev, S. F. Ganzhur, V. N. Ivanchenko, A. A. Korol,
E. A. Kravchenko, A. P. Onuchin, S. I. Serednyakov, Yu. I. Skovpen, V. I. Telnov
California Institute of Technology, Pasadena, California, USA
E. Chen, G. P. Dubois-Felsmann, D. G. Hitlin, Y. G. Kolomensky, S. Metzler, B. B. Naranjo,
F. C. Porter, A. Ryd, A. Samuel, M. Weaver, S. Yang, R. Zhu
University of California, Irvine, Irvine, California, USA
A. Lankford, M. Mandelkern, D.P. Stoker, G. Zioulas
University of California, Los Angeles, Los Angeles, California, USA
C. Buchanan, S. Chun


iv
University of California, San Diego, La Jolla, California, USA
J. G. Branson, R. Faccini, C. Hast, D. B. MacFarlane, E. Potter, S. Rahatlou, G. Raven,
V. Sharma, F. Wilson
University of California, Santa Barbara, Santa Barbara, California, USA
D.A. Bauer, C. Campagnari, A. Eppich, P. Hart, N. Kuznetsova, O. Long, A. Lu, J.D. Richman,
M. Witherell, S. Yellin
University of California, Santa Cruz, Santa Cruz, California, USA
J. Beringer, D. E. Dorfan, A. M. Eisner, A. Frey, A. A. Grillo, C. A. Heusch, R. P. Johnson,
W. S. Lockman, M. Munson, T. Pulliam, H. Sadrozinski, T. Schalk, B. A. Schumm, A. Seiden,
M. Turri
University of Cincinnati, Cincinnati, Ohio, USA
S. Devmal, T. Geld, B. T. Meadows, D. Renner, M. D. Sokoloff
Colorado State University, Fort Collins, Colorado, USA

J. L. Harton, R. Malchow, A. Soffer, W. H. Toki, R. J. Wilson, W. Yang
University of Colorado, Boulder, Colorado, USA
S. Fahey, W. T. Ford, F. Gaede, K. M. Hall, T. L. Hall, D. R. Johnson, H. Krieg, U. Nauenberg,
P. Rankin, J. Roy, S. Sen, J. G. Smith, D. L. Wagner, M. Zhao
Technische Universit¨at Dresden, Dresden, Germany
T. Brandt, J. Brose, M. L. Kocian, R. M¨uller-Pfefferkorn, K. R. Schubert, R. Schwierz, B. Spaan,
R. Waldi
University of Edinburgh, Edinburgh, UK
R. Bernet, P. Clark, S. Gowdy, S. Playfer
INFN Sezione di Ferrara, Ferrara, Italy
S. Dittongo, M. Folegani, L. Piemontese
INFN Laboratori Nazionali di Frascati, Frascati, Italy
F. Anulli, A. Asmone, R. Baldini-Ferroli, A. Calcaterra, D. Falciai, G. Finocchiaro, I. M. Peruzzi,
M. Piccolo, R. de Sangro, Z. Yu, A. Zallo
INFN Sezione di Genova, Genova, Italy
A. Buzzo, R. Contri, G. Crosetti, M. Lo Vetere, M. Macri, M. R. Monge, M. Pallavicini,
R. Parodi, C. Patrignani, M. G. Pia, E. Robutti, A. Santroni
Imperial College, London, UK
P. D. Dauncey, R. Martin, J.A. Nash, P. Sanders, D. Smith, P. Strother
Iowa State University, Ames, Iowa, USA
H. B. Crawley, A. Firestone, J. Lamsa, W. T. Meyer, E. I. Rosenberg

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University of Iowa, Iowa City, Iowa, USA
R. Bartoldus, T. Dignan, R. Hamilton, U. Mallik
Lawrence Berkeley National Laboratory, Berkeley, California, USA
B. Abbott, G. S. Abrams, A. Breon, D. N. Brown, R. N. Cahn, A. R. Clark, C. T. Day, Q. Fan,
R. G. Jacobsen, R. W. Kadel, J. Kadyk, R. Kapur, A. Karcher, R. Kerth, S. Kluth, J. F. Kral,
C. LeClerc, M. Levi, D. Li, T. Liu, G. Lynch, M. Marino, A. Meyer, A. Mokhtarani, P. J. Oddone,
J. Ohnemus, S. J. Patton, M. Pripstein, D. R. Quarrie, N. A. Roe, A. Romosan, M. Ronan,
V. G. Shelkov, A. V. Telnov, W. A. Wenzel
Lawrence Livermore National Laboratory, Livermore, California, USA
P. D. Barnes, R. M. Bionta, D. Fujino, M. N. Kreisler, M. Mugge, X. Shi, K. A. Van Bibber,
D. Wright, C. R. Wuest
University of Liverpool, Liverpool, UK
M. Carroll, G. Dahlinger, J. R. Fry, E. Gabathuler, R. Gamet, M. George, S. McMahon,
C. Touramanis
University of Louisville, Louisville, Kentucky
D. Brown, C. Davis, J. Pavlovich, A. Trunov
University of Manchester, Manchester, UK
J. Allison, R. Barlow, A. Khan, G. Lafferty, A. McNab, N. Savvas, A. Walkden, J. Weatherall
University of Maryland, College Park, Maryland, USA
C. Dallapiccola, D. Fong, A. Jawahery, D. A. Roberts, A. Skuja
Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
R. F. Cowan, R. K. Yamamoto
University of Massachusetts, Amherst, Amherst, Massachusetts, USA
K. Baird, G. Blaylock, J. Button-Shafer, K. Flood, S. S. Hertzbach, R. Kofler, C. S. Lin, J. Wittlin
McGill University, Montr´eal, Quebec, Canada
P. Bloom, M. Milek, P. M. Patel, J. Trischuk
INFN Sezione di Milano, Milano, Italy
A. Forti, F. Lanni, F. Palombo, V. Pozdnyakov
University of Mississippi, University, Mississippi, USA
J. M. Bauer, L. Cremaldi, V. Eschenburg, R. Kroeger, J. Reidy, D. Sanders, J. Secrest,

D. Summers
Universit´e of Montr´eal, Montr´eal, Quebec, Canada
A. Hasan, J. Martin, R. Seitz, P. Taras, A. Woch, V. Zacek

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Mount Holyoke College, South Hadley, Massachusetts, USA
H. Nicholson, C. S. Sutton
INFN Sezione di Napoli, Napoli, Italy
G. P. Carlino, N. Cavallo, G. De Nardo, F. Fabozzi, C. Gatto, L. Lista, P. Paolucci, D. Piccolo,
C. Sciacca
Northern Kentucky University, Highland Heights, Kentucky, USA
M. Falbo-Kenkel
University of Notre Dame, Notre Dame, Indiana
J. Bishop, N. M. Cason, A. Garcia, J. M. LoSecco, W. D. Shephard
Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
R. Alsmiller, T. A. Gabriel
LAL Orsay, Orsay, France
M. Benkebil, G. Grosdidier, A. Hoecker, V. Lepeltier, A. Lutz, S. Plaszczynski, M.-H. Schune,
A. Valassi, G. Wormser, F. Zomer
INFN Sezione di Padova, Padova, Italy
F. Dal Corso, F. Galeazzi, M. Morandin, M. Posocco, R. Stroili, C. Voci
Ecole Polytechnique Palaiseau, LPNHE, Palaiseau, France
L. Behr, G. R. Bonneaud, E. Roussot, C. Thiebaux, G. Vasileiadis, M. Verderi

LPNHE Universit´e de Paris VI et VII, Paris, France
M. Benayoun, H. Briand, J. Chauveau, P. David, C. de la Vaissi`ere, L. Del Buono, O. Hamon,
F. Le Diberder, Ph. Leruste, J. Lory, L. Martin, J.-L. Narjoux, N. Regnault, L. Roos, S. Versill´e
INFN Sezione di Pavia, Pavia, Italy
A. Leona, A. Leona, E. Mandelli, P. F. Manfredi, A. Perazzo, L. Ratti, V. Re, V. Speziali
University of Pennsylvania, Philadelphia, Pennsylvania, USA
C. Cretsinger, E. Frank, L. Gladney, V. Suraiya
INFN Sezione di Pisa, Pisa, Italy
C. Angelini, G. Batignani, S. Bettarini, M. Bondioli, G. Calderini, M. Carpinelli, F. Costantini,
F. Dutra, F. Forti, M. A. Giorgi, A. Lusiani, S. Mettarini, M. Morganti, F. Morsani, M. Rama,
G. Rizzo, G. Simi, G. Triggiani, R. Vitale
Prairie View A& M University, Prairie View, Texas, USA
M. Haire, D. Judd, K. Paick, D. Wagoner
Princeton University, Princeton, New Jersey, USA
J. Albert, C. Lu, K. T. McDonald, V. Miftakov, S. F. Schaffner, A. J. S. Smith, A. Tumanov,
E. W. Varnes
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Queen Mary & Westfield College, London, UK
J. J. Back, P. F. Harrison, A. J. Martin
University di Roma ‘La Sapienza’ and INFN Sezione di Roma, Rome, Italy G. Cavoto,
F. Ferrarotto, F. Ferroni, E. Lamanna, S. Mazzoni, S. Morganti, G. Piredda, M. Rotondo
Royal Holloway & Bedford New College, London, UK
M. G. Green, I. Scott, E. Tetteh-Lartey

Rutgers University, Rutgers, New Jersey, USA
P. F. Jacques, M. S. Kalelkar, G. Mancinelli, R. J. Plano
Rutherford Appleton Laboratory, Chilton, Didcot, UK
T. Adye, U. Egede, B. Franek, N. I. Geddes, G. P. Gopal
CEA, DAPNIA, CE-Saclay, Gif-sur-Yvette, France
R. Aleksan, G. De Domenico, S. Emery, A. Gaidot, G. Hamel de Monchenault, A. de Lesquen,
G.W. London, B. Mayer, A. Salnikov, G. H. Vasseur, C. Yeche, M. Zito
Shanghai Institute of Ceramics (SICCAS), Shanghai, China
D. Yan, Z. Yin
University of South Carolina, Columbia, South Carolina, USA
N. Copty, M. Purohit
Stanford Linear Accelerator Center, Stanford, California, USA
I. Adam, P. L. Anthony, D. Aston, A. Bajic, E. Bloom, A. M. Boyarski, F. Bulos,
J. Cohen-Tanugi, M. R. Convery, D. P. Coupal, D. H. Coward, N. De Groot, J. Dorfan, M. Doser,
W. Dunwoodie, T. Glanzman, G. L. Godfrey, J. L. Hewett, T. Himel, W. R. Innes, C. P. Jessop,
L. Keller, P. C. Kim, P. F. Kunz, W. G. J. Langeveld, D. W. G. S. Leith, K. Lingel, V. Luth,
H. L. Lynch, G. Manzin, H. Marsiske, T.S. Mattison, R. Messner, K. Moffeit, M. Morii,
R. Mount, D.R. Muller, C.P. 0’Grady, T.J. Pavel, R. Pitthan, B. N. Ratcliff, L. S. Rochester,
V. Savinov, R. H. Schindler, J. Schwiening, G. Sciolla, V. V. Serbo, A. Snyder, A. Stahl, D. Su,
M. K. Sullivan, M. Talby, H. A. Tanaka, J. Va’vra, S. R. Wagner, A. Weinstein, W. J. Wisniewski,
C. C. Young
Stanford University, Stanford, California, USA
P. Burchat, C. H. Cheng, D. Kirkby, T. I. Meyer, E. Nehrlich, C. Roat, R. Zaliznyak
University of Texas, Dallas, Dallas, Texas, USA
J. H. Cooke III, J. M. Izen, X. C. Lou, M. Turcotte
INFN Sezione di Torino, Torino, Italy
F. Bianchi, B. DiGirolamo, D. Gamba, P. Grosso, A. Romero, A. Smol, A. Vitelli, D. Zanin

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INFN Sezione di Trieste, Trieste, Italy
L. Bosisio, G. Castelli, G. Della Ricca, L. Lanceri, G. Musolino, P. Poropat, M. Prest, E. Vallazza,
G. Vuagnin
TRIUMF, Vancouver, British Columbia, Canada
R. Henderson
Vanderbilt University, Nashville, Tennessee, USA
R. S. Panvini
University of Victoria, Victoria, British Columbia, Canada
A. DeSilva, R. V. Kowalewski, J. M. Roney
University of Wisconsin, Madison, Madison, Wisconsin, USA
H. Band, E. Charles, S. Dasu, P. Elmer, J. Johnson, J. Nielsen, W. Orejudos, Y. Pan, R. Prepost,
I. Scott, J. Walsh, S. L. Wu, H. Zobernig

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Participating Theorists
D. Atwood, Iowa State University; P. Ball, European Laboratory for Particle Physics, CERN;
I. Bigi, University of Notre Dame; F. M. Borzumati, Universit¨at Z¨urich; C. G. Boyd, Carnegie
Mellon University; G. C. Branco, Instituto Superior T´ecnico, Lisbon; V. M. Braun, Nordisk Institut

for Teoretisk Fysik, NORDITA; F. Buccella, INFN Sezione di Naples; G. Buchalla, European Laboratory for Particle Physics, CERN; G. Burdman, University of Wisconsin; R. N. Cahn, Lawrence
Berkeley National Laboratory; J. Charles, Laboratoire de Physique Th´eorique et Hautes Energies, Orsay; M. Ciuchini, INFN Sezione di Rome; F. E. Close, Rutherford Appelton Laboratory;
P. Colangelo, INFN Sezione di Bari; F. De Fazio, INFN Sezione di Bari; A. S. Dighe, International Centre for Theoretical Physics, Trieste; I. Dunietz, Fermi National Accelerator Laboratory;
A. F. Falk, Johns Hopkins University; R. Fleischer, European Laboratory for Particle Physics,
CERN; J. M. Flynn, University of Southampton; M. C. Gonzalez-Garcia, Universidad de Val`encia;
B. Grinstein, University of California, San Diego; Y. Grossman, Stanford Linear Accelerator
Center; D. Guetta, INFN Sezione di Bologna; J. L. Hewett, Stanford Linear Accelerator Center;
G. Isidori, Laboratori Nazionali de Frascati; A. L. Kagan, University of Cincinnati; Y. Y. Keum,
APCPT, Seoul National University; A. Khodjamirian, Universit¨at W¨urzburg; J. H. K¨uhn, Universit¨at Karlsruhe; A. Le Yaouanc, Laboratoire de Physique Th´eorique et Hautes Energies, Orsay;
L. Lellouch, European Laboratory for Particle Physics, CERN; Z. Ligeti, University of California,
San Diego; D. London, Universit´e de Montr´eal; M. Lusignoli, INFN Sezione di Rome; T. Mannel, Universit¨at Karlsruhe, G. Martinelli, INFN Sezione di Rome; A. Masiero, INFN Sezione
di Padova; B. Mayer, Centre d’Etudes Nucl´eaires de Saclay; G. Michelon, International Centre
for Theoretical Physics, Trieste; E. Mirkes, Universit¨at Karlsruhe; E. Nardi, Antioquia University; M. Neubert, European Laboratory for Particle Physics, CERN; U. Nierste, DESY Deutsches
Elektronen-Synchrotron; Y. Nir, The Weizmann Institute of Science; L. Oliver, Laboratoire de
Physique Th´eorique et Hautes Energies, Orsay; N. Paver, INFN Sezione di Trieste; R. D. Peccei,
University of California, Los Angeles; O. Pene, Laboratoire de Physique Th´eorique et Hautes
Energies, Orsay; A. A. Petrov, Johns Hopkins University; A. Pich, Universidad de Val`encia;
A. Pugliese, INFN Sezione di Rome; H. R. Quinn, Stanford Linear Accelerator Center; L. Reina,
University of Wisconsin; G. Ricciardi, INFN Sezione di Naples; T. G. Rizzo, Stanford Linear
Accelerator Center; R. R¨uckl, Universit¨at W¨urzburg; C. T. Sachrajda, University of Southampton; D. Silverman, University of California, Irvine; L. Silvestrini, Universit`a di Roma; A. Soni,
Brookhaven National Laboratory; B. F.L. Ward, University of Tennessee; J. D. Wells, Stanford
Linear Accelerator Center; M. B. Wise, California Institute of Technology; M. P. Worah,Stanford
Linear Accelerator Center; D. Wyler, Universit¨at Z¨urich


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Preface
This book presents the results of a year-long workshop devoted to a review of the physics opportunities of the BABAR experiment at the PEP-II B Factory, at the Stanford Linear Accelerator Center
laboratory. The workshop meeting schedule was as follows:
University of Rome “La Sapienza” 11th–14th November 1996
Princeton University
17th–20th March 1997
LAL Orsay
16th–19th June 1997
California Institute of Technology 22nd–24th September 1997
The workshop brought together a number of theorists with experimentalists from the BABAR Collaboration. Each chapter represents the contribution of a working group and presents both a theoretical
summary of the relevant topics and the results of related simulation studies. The working group
convenors, listed below, were teams that included both theorists and experimentalists.
The book represents the status of work around the beginning of 1998. Both the state of the theory
and of the experiment’s simulation and analysis tools continue to advance. The results presented
here are thus not a final view of what the experiment can achieve, but represent an interim study.
The studies are more detailed and comprehensive than those made at the time of the Technical
Design Report, but still lack many features that will be needed for the real data analysis. The book
is intended as a guide to the work that still needs to be done, and as a detailed introduction which
will assist new members, joining the Collaboration, and, we hope, other researchers in the field.


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Working Groups and Conveners
The BABAR workshops were divided into the following working groups with the conveners named.
Chapters 5–12 and 14 of this book directly represent the work done in these groups.
Determinations of
Y. Karyotakis, L. Oliver, J. Smith, W. Toki
Determinations of and Direct CP Violation.
M. Giorgi, H. Jawahery, F. LeDiberder, D. London, A. Soni
Methods of Measuring
P. Dauncey, R. Fleischer, L. Lanceri

Semileptonic B Decays and the Extraction of Vub , Vcb from B decays
T. Mannel, M. Neubert, K. Schubert, M. Witherell
Rare B Decays within the Standard Model
J. Hewett, A. Masiero, S. Playfer, S. Wagner

Hadronic B Meson Decays
I. Bigi, A. Petrov, P. Rankin, R. Waldi, D. Wyler

Non-CP B Physics
J. Chauveau, J. Izen, G. Martinelli, U. Nierste

Charm, , QCD and Two-photon Physics
P. Burchat, F. Gilman, R. Peccei, A. Pich, A. Seiden
Overall Determinations of the CKM Matrix
G. Eigen, B. Grinstein, Y. Nir, M. Schune
In addition, Chapter 1 was convened by H. Quinn and Y. Nir; Chapter 2 was convened by A. Falk,

and Chapters 3 and 4 were convened by P. F. Harrison and M. Pia. Chapter 13 was convened by
J. Hewett, A. Masiero, and Y. Nir.


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Acknowledgments
Preliminary organisation of the BABAR workshops was managed by the International Organising
Committee:
Roy Aleksan
Marcello Giorgi
Paul Harrison (Program Coordinator)
David Hitlin
Helen Quinn (Theory Coordinator)
Klaus Schubert
Marie-Helene Schune
Walter Toki
Mike Witherell
The organisers gratefully acknowledge the financial support of:
Accademia Nazionale dei Lincei
California Institute of Technology
DAPNIA-Saclay/CEA
Dipartimento di Fisica dell’Universit`a di Roma “La Sapienza”

IN2P3/CNRS
Istituto Nazionale di Fisica Nucleare
National Science Foundation
Princeton University Physics Department


xvi
Particle Physics and Astronomy Research Council
Universit´e de Paris XI, Orsay
US Department of Energy
and of the local workshops organisations:
Dipartimento di Fisica dell’Universit`a di Roma “La Sapienza”: Gabriella Bucci and Marcella
Mastrofini and staff
Princeton University: Elaine Remillard and staff
Laboratoire de l’Acc´el´erateur Lin´eaire (LAL), Orsay: Marie-Helene Schune and her local
organizing committee and Nicole Mathieu and her staff.
California Institute of Technology: Betty Smith and staff
The editors would like to thank particularly Bob Cahn, Theresa Champion, Adam Falk, Klaus
Schubert, and Jim Smith for their assistance during the editing of this Book. They would also
like to thank Sharon Jensen of the SLAC Theory Group and the production staff of the SLAC
Technical Publications Department for their invaluable and indefatigable work during the editing
and production of the book.

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Contents
1 A CP Violation Primer
1.1

CP Violation in Field Theories

. . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Field Transformations . . . . . . . . . . . . . . . . . . . . . . . . . .

2

Neutral B Mesons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

1.2.1

Mixing of Neutral B Mesons . . . . . . . . . . . . . . . . . . . . . . .

5

1.2.2

Phase Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

1.2.3

Time Evolution of Neutral Bd Mesons . . . . . . . . . . . . . . . . . .

8

1.2.4

Two-Time Formalism for Coherent BB States . . . . . . . . . . . . .

9

1.1.1
1.2

1.3

1

The Three Types of CP Violation in B Decays . . . . . . . . . . . . . . . . . . . 12
1.3.1
1.3.2
1.3.3

CP Violation in Decay . . . . . . . . . . . . . . . . . . . . . . . . . .
CP Violation in Mixing . . . . . . . . . . . . . . . . . . . . . . . . .
CP Violation in the Interference Between Decays With and Without

12
14

Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.4

1.5

CP Violation in the Standard Model . . . . .
1.4.1
The CKM Picture of CP Violation .

. . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . . 17

1.4.2

Unitarity of the CKM Matrix . . . . . . . . . . . . . . . . . . . . . . . 19

1.4.3

Measuring CKM Parameters with CP -Conserving Processes . . . . . . 23

Expected CP Asymmetries — Standard Model Predictions . . . . . . . . . . . . 24
1.5.1

CP Violation in Mixing

1.5.2

Decay-Amplitude Weak-Phase Structure . . . . . . . . . . . . . . . . . 25

1.5.3

Low-Energy Effective Hamiltonians . . . . . . . . . . . . . . . . . . . 28

1.5.4

Decay Asymmetry Predictions in the Standard Model —
General Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

. . . . . . . . . . . . . . . . . . . . . . . . . 24


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1.6

1.5.5

Decay Asymmetry Predictions in the Standard Model —
Some Sample Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

1.5.6

Effects of Physics Beyond the Standard Model . . . . . . . . . . . . . 34

Some Comments about the K System . . . . . . . . . . . . . . . . . . . . . . . 35
1.6.1

The Neutral K System . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.6.2

Measuring CP Violation in the K System . . . . . . . . . . . . . . . . 37

1.6.3

The "K and "0K Parameters . . . . . . . . . . . . . . . . . . . . . . . . 38

2 Introduction to Hadronic B Physics
2.1

2.2

2.3

43

The Operator Product Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.1.1

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 46

2.1.2

Example I: Weak b Decays . . . . . . . . . . . . . . . . . . . . . . . . 47

2.1.3

Radiative Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.1.4

Example II: Penguins and Box Diagrams . . . . . . . . . . . . . . . . 50

2.1.5

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

The Heavy-Quark Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.1

Separation of Scales . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

2.2.2

Heavy-Quark Symmetry . . . . . . . . . . . . . . . . . . . . . . . . . 53

2.2.3

Heavy-Quark Effective Theory . . . . . . . . . . . . . . . . . . . . . . 54

2.2.4

Application of the HQE to B Decays . . . . . . . . . . . . . . . . . . 56

2.2.5

Limitations of the HQE . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Light Flavor Symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

2.3.1

Chiral Lagrangians . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

2.3.2

Heavy-Hadron Chiral Perturbation Theory . . . . . . . . . . . . . . . 61

2.3.3

Factorization, Color Flow, and Vacuum Saturation . . . . . . . . . . . 62

2.4

Lattice Gauge Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

2.5

QCD Sum Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

R EPORT

OF THE

BABAR P HYSICS WORKSHOP


xix
2.6

Quark Models and Related Methods . . . . . . . . . . . . . . . . . . . . . . . . 68

2.7

Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

3 An Introduction to the BABAR Experiment
3.1

e e, B Factories and PEP-II
+

73

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

4S

3.1.1

Cross-Sections at the 

3.1.2

Data Taking in the Continuum . . . . . . . . . . . . . . . . . . . . . . 75

. . . . . . . . . . . . . . . . . . . . . . . 74

3.2

Overview of the BABAR Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.3

The Silicon Vertex Tracker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

3.4

3.5

3.6

3.3.1

Physics Requirements and Performance Goals . . . . . . . . . . . . . . 81

3.3.2

Silicon Vertex Tracker Layout . . . . . . . . . . . . . . . . . . . . . . 82

3.3.3

The Silicon Microstrip Detectors . . . . . . . . . . . . . . . . . . . . . 84

3.3.4

Silicon Vertex Tracker Readout . . . . . . . . . . . . . . . . . . . . . 85

3.3.5

Silicon Vertex Tracker Space Resolution . . . . . . . . . . . . . . . . . 86

3.3.6

Calibration and Alignment . . . . . . . . . . . . . . . . . . . . . . . . 88

The Drift Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
3.4.1

Drift Chamber Design . . . . . . . . . . . . . . . . . . . . . . . . . . 89

3.4.2

Drift Chamber Electronics . . . . . . . . . . . . . . . . . . . . . . . . 92

3.4.3

Prototype Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

The DIRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
3.5.1

DIRC Concept and Hardware Overview . . . . . . . . . . . . . . . . . 94

3.5.2

DIRC Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

3.5.3

DIRC Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

The Electromagnetic Calorimeter . . . . . . . . . . . . . . . . . . . . . . . . . . 96
3.6.1

Performance Goals and Layout . . . . . . . . . . . . . . . . . . . . . . 96

3.6.2

Crystal Subassemblies and Readout . . . . . . . . . . . . . . . . . . . 99

3.6.3

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

R EPORT

OF THE

BABAR P HYSICS WORKSHOP


xx
3.7

3.8

The Muon and Neutral Hadron Detector . . . . . . . . . . . . . . . . . . . . . . 102
3.7.1

The Detector Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

3.7.2

The Active Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

3.7.3

The Readout System . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

The Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

4 Snapshot of BABAR Software and Analysis Tools
4.1

4.2

4.3

4.4

Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
4.1.1

Event Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

4.1.2

Full Detector Simulation . . . . . . . . . . . . . . . . . . . . . . . . . 113

4.1.3

Fast Detector Simulation: Aslund . . . . . . . . . . . . . . . . . . . 115

Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
4.2.1

Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

4.2.2

Reconstruction in the Electromagnetic Calorimeter . . . . . . . . . . . 121

Charged Particle Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.3.1

Charged Hadron Identification . . . . . . . . . . . . . . . . . . . . . . 126

4.3.2

Electron Identification . . . . . . . . . . . . . . . . . . . . . . . . . . 129

4.3.3

Muon Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

4.3.4

Identification of Particles with Neural Networks . . . . . . . . . . . . . 138

Neutral Particle Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
4.4.1
4.4.2

4.5

4.6

 and Photon Identification
KL Identification . . . . . .
0

0

. . . . . . . . . . . . . . . . . . . . . . . 144
. . . . . . . . . . . . . . . . . . . . . . . 145

Vertexing and Kinematic Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.5.1

Vertex Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . 153

4.5.2

Kinematical Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Reconstruction of Particle Decays . . . . . . . . . . . . . . . . . . . . . . . . . 159
4.6.1

R EPORT

111

OF THE

KS

0

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

BABAR P HYSICS WORKSHOP


xxi
4.6.2
4.7

4.8

4.9

4.10

4.11

D and D

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Multivariate Analysis Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.7.1

Presentation of the Different Methods . . . . . . . . . . . . . . . . . . 165

4.7.2

Description of Cornelius . . . . . . . . . . . . . . . . . . . . . . . 169

Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
4.8.1

Direct- and Reverse-Sign Classes . . . . . . . . . . . . . . . . . . . . 171

4.8.2

The Tagging Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

4.8.3

Definition of Discriminating Variables

4.8.4

Definition of Categories of Events Treated . . . . . . . . . . . . . . . . 175

4.8.5

Performances of the Tagging Methods . . . . . . . . . . . . . . . . . . 176

4.8.6

Measuring the Tagging Performance with Real Data . . . . . . . . . . 178

4.8.7

Future Prospects and Improvements . . . . . . . . . . . . . . . . . . . 180

4.8.8

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

. . . . . . . . . . . . . . . . . 173

Tools for Continuum Identification . . . . . . . . . . . . . . . . . . . . . . . . . 181
4.9.1

Criteria for Continuum Identification . . . . . . . . . . . . . . . . . . 181

4.9.2

A Common Procedure for Background Fighting . . . . . . . . . . . . . 185

4.9.3

Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

Extraction of CP Asymmetries . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
4.10.1

Fit Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

4.10.2

Adding Flavor-Tagging Information . . . . . . . . . . . . . . . . . . . 189

4.10.3

Likelihood Estimate of A . . . . . . . . . . . . . . . . . . . . . . . . . 190

4.10.4

Error of the Likelihood Estimate . . . . . . . . . . . . . . . . . . . . . 191

4.10.5

The Kin Variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Data Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

5 Determination of
5.1

Theoretical Review of

199

sin2

Measurements . . . . . . . . . . . . . . . . . . . . 199

R EPORT

OF THE

BABAR P HYSICS WORKSHOP


xxii
5.1.1

Decays That Can Measure

. . . . . . . . . . . . . . . . . . . . . . . 199

5.1.2

Uncertainties: Penguins and FSI phases . . . . . . . . . . . . . . . . . 204

5.1.3

Angular Analyses to Extract CP Amplitudes . . . . . . . . . . . . . . 213

5.1.4

Isospin Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

5.1.5

Modeling the Uncertainty on

5.1.6

Measurement of

5.1.7

Discrete Ambiguities . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

5.1.8

Summary of Data on Decays Measuring

. . . . . . . . . . . . . . . . . . . . . . 222

in Inclusive Decays . . . . . . . . . . . . . . . . . . 229

sin2

. . . . . . . . . . . . . . . . 236

5.2

Experimental Considerations for

5.3

Charmonium + Kaon modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
5.3.1
5.3.2

5.3.3
5.3.4

5.4

5.5

B
B
B
B

0
0
0
0

! J= KS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
! J= KL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
! 0KL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
! KL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
0
0

0

0

c1

Charmonium + K 0 Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
5.4.1

Event Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

5.4.2

Measurement of

with the Decay B 0

+

+

0

! J=K 

+

0

. . . . . . . . . 264

. . . . . . . . . . 265
. . . . . . . . . . 265
. . . . . . . . . . 275
. . . . . . . . . . 291
. . . . . . . . . 292

Penguin Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

5.6.2

! 0KS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
Analysis of B !  0 KL . . . . . . . . . . . . . . . . . . . . . . . . . 306

5.6.3

Analysis of

5.6.1

R EPORT

sin2

D D,, DD, and DD Final States . . . . . . . . . . . . .
5.5.1
Study of B ! D D, . . . . . . . . . . . . . . . .
5.5.2
Study of B ! D D, . . . . . . . . . . . . . . .
5.5.3
Estimates for the D D Mode . . . . . . . . . . . . .
5.5.4
Measurement of CP Asymmetries and Extraction of
0

5.6

Analyses . . . . . . . . . . . . . . . . . 241

OF THE

B

0

0

0

K

0

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

BABAR P HYSICS WORKSHOP


xxiii

5.7

5.6.4

Estimates for B

5.6.5

Analysis of B 0

6.2

6.3
6.4

0

0

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
5.7.1

Summary of Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

5.7.2

Systematic Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

5.7.3

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

6 Determinations of
6.1

! KS . . . . . . . . . . . . . . . . . . . . . . . . . 315

! KL . . . . . . . . . . . . . . . . . . . . . . . . . . 315

and Direct CP Violation

327

Theoretical Background: The Role of Penguins and -Extraction . . . . . . . . . 327
6.1.1

Extraction of -Ignoring Penguins . . . . . . . . . . . . . . . . . . . . 328

6.1.2

Extraction of

in the Presence of Penguins . . . . . . . . . . . . . . . 330

Penguins and Direct CP Violation . . . . . . . . . . . . . . . . . . . . . . . . . 346
6.2.1

Varieties of Direct CP Violation . . . . . . . . . . . . . . . . . . . . . 346

6.2.2

Illustrative Examples of Direct CP . . . . . . . . . . . . . . . . . . . . 348

Overview of the Experimental Studies . . . . . . . . . . . . . . . . . . . . . . . 353

B -Decay Modes with Two Pions . . . . . . . . . . . . . . . . . . . . . . . .
6.4.1

The   , Decay Mode . . . . . . . . . . . . . . . . . . . . . . .
6.4.2
The   Decay Mode . . . . . . . . . . . . . . . . . . . . . . . .
6.4.3
The   Decay Mode . . . . . . . . . . . . . . . . . . . . . . . .
6.4.4
Extraction of CP Asymmetries from the B !   , Decay Mode .
+
0

+

0

0

0

6.4.5
6.4.6
6.4.7
6.5

+

. . 353
. . 354
. . 359
. . 361
. . 364

Isospin Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
without B 0

!   ? . . . . . . . . . . . . . . . . . . . . . . . . . . 370
0

0

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376

B Decay Modes with Three Pions

. . . . . . . . . . . . . . . . . . . . . . . . . 376

6.5.1

Event Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378

6.5.2

Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388

6.5.3

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

R EPORT

OF THE

BABAR P HYSICS WORKSHOP


xxiv
6.6

B -Decay Modes with Four Pions

. . . . . . . . . . . . . . . . . . . . . . . . . . 404

6.6.1

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

6.6.2

The 1  Decay Modes . . . . . . . . . . . . . . . . . . . . . . . . . . 405

6.6.3

The

6.6.4

Summary and Conclusion for Four-Pion Channels . . . . . . . . . . . 437

a

Decay Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . 429

6.7

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438

6.8

Charged B Decays and Direct CP Violation . . . . . . . . . . . . . . . . . . . . 441

6.8.2

B , ! h, .
B , ! D, D

6.8.3

Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444

6.8.1

0

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443

7 Methods of Measuring

449
. . . . . . . . . . . . . . . . . . . 449

7.1

Introduction and Motivation for Measuring

7.2

An Overview of Methods for Extracting

7.3

Experimental Errors in Extracting

from Triangles . . . . . . . . . . . . . . . . 453

7.4

Methods Using B

. . . . . . . . . . . . . . . . . . . . . . . . . 456

7.5

7.6

7.7

R EPORT

! DK Decays

. . . . . . . . . . . . . . . . . . . . . 449

7.4.1

Theoretical Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 456

7.4.2

Experimental Feasibility Studies . . . . . . . . . . . . . . . . . . . . . 460

Methods Using Flavor Symmetries . . . . . . . . . . . . . . . . . . . . . . . . . 466
7.5.1

Theoretical Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 466

7.5.2

A Simple Strategy for Extracting

7.5.3

Constraints from Combined Bu;d

7.5.4

Experimental Feasibility Studies . . . . . . . . . . . . . . . . . . . . . 478

Partial Reconstruction of Bd

. . . . . . . . . . . . . . . . . . . 470

! K Branching Ratios . . . . . . . 473

! D   . . . . . . . . . . . . . . . . . . . . . . 481
 

7.6.1

Theoretical Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 483

7.6.2

The Experimental Approach . . . . . . . . . . . . . . . . . . . . . . . 484

Strategies to Determine

OF THE

from Bs Decays . . . . . . . . . . . . . . . . . . . . . 491

BABAR P HYSICS WORKSHOP


xxv
7.8

Summary of Results and Overall

Reach . . . . . . . . . . . . . . . . . . . . . 493

8 Semileptonic B Decays and the Extraction of
8.1

8.2

8.3

jV j and jV j
cb

499

ub

Exclusive Semileptonic B Decays to Charmed Mesons . . . . . . . . . . . . . . 499
8.1.1

Heavy-Quark Symmetry . . . . . . . . . . . . . . . . . . . . . . . . . 499

8.1.2

Determination of

8.1.3

Dispersive Bounds and Unitarity Constraints on Form Factors . . . . . 505

8.1.4

Tests of Heavy-Quark Symmetry . . . . . . . . . . . . . . . . . . . . . 507

8.1.5

B

jV j
cb

. . . . . . . . . . . . . . . . . . . . . . . . . . 502

Decays to p-Wave Charm Mesons . . . . . . . . . . . . . . . . . . 508

Exclusive Semileptonic B Decays to Light Mesons and Determination of

jV j . . 512
ub

8.2.1

Heavy-to-Light Form Factors from Lattice QCD . . . . . . . . . . . . 513

8.2.2

Dispersive Bounds on Heavy-to-Light Form Factors . . . . . . . . . . 515

8.2.3

Heavy-to-Light Form Factors from Light-Cone Sum Rules . . . . . . . 517

8.2.4

Using Semileptonic D Decays and Dispersive Bounds to Extract

8.3.2

ub

! c Decays . . . . . . . . . . . . . . . . . . . . . . . . 521
Determination of jV j . . . . . . . . . . . . . . . . . . . . . . . . . . 526

Inclusive Semileptonic b
8.3.1

jV j . 520

cb

Aspects of Inclusive B Decays . . . . . . . . . . . . . . . . . . . . . 529

8.4

jV j from Inclusive Semileptonic b ! u Decays . . . . . . . . . . . . . . . . . . 530

8.5

Theory Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532

8.6

Studying Semileptonic Decays with the BABAR Detector . . . . . . . . . . . . . . 534

8.7
8.8
8.9
8.10

ub

8.6.1

The Experimental Environment . . . . . . . . . . . . . . . . . . . . . 534

8.6.2

Semileptonic Event Generators . . . . . . . . . . . . . . . . . . . . . . 534

8.6.3

Reconstruction of the Other B . . . . . . . . . . . . . . . . . . . . . . 535

jV
Measuring jV
Measuring jV
Measuring jV
Measuring

cb

j Using HQET in Exclusive Decays . . . . . . . . . . . . . . . . . 538
j Using Exclusive Decays . . . . . . . . . . . . . . . . . . . . . . 539

j with Inclusive Decays . . . . . . . . . . . . . . . . . . . . . . . 540
j with Inclusive Decays . . . . . . . . . . . . . . . . . . . . . . . 544

ub
cb

ub

R EPORT

OF THE

BABAR P HYSICS WORKSHOP