Measurement of branching ratio and $B_{s}^{0}$ lifetime in the decay $B_{s}^{0} \to J / ψ f_{0} (980)$ at CDF

T. Aaltonen Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland B. Álvarez González

^{w}

Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain S. Amerio Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy D. Amidei University of Michigan, Ann Arbor, Michigan 48109, USA A. Anastassov Northwestern University, Evanston, Illinois 60208, USA A. Annovi Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy J. Antos Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia G. Apollinari Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J.A. Appel Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Apresyan Purdue University, West Lafayette, Indiana 47907, USA T. Arisawa Waseda University, Tokyo 169, Japan A. Artikov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia J. Asaadi Texas A&M University, College Station, Texas 77843, USA W. Ashmanskas Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA B. Auerbach Yale University, New Haven, Connecticut 06520, USA A. Aurisano Texas A&M University, College Station, Texas 77843, USA F. Azfar University of Oxford, Oxford OX1 3RH, United Kingdom W. Badgett Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Barbaro-Galtieri Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA V.E. Barnes Purdue University, West Lafayette, Indiana 47907, USA B.A. Barnett The Johns Hopkins University, Baltimore, Maryland 21218, USA P. Barria

^{d d}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy P. Bartos Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia M. Bauce

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy G. Bauer Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA F. Bedeschi Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy D. Beecher University College London, London WC1E 6BT, United Kingdom S. Behari The Johns Hopkins University, Baltimore, Maryland 21218, USA G. Bellettini

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy J. Bellinger University of Wisconsin, Madison, Wisconsin 53706, USA D. Benjamin Duke University, Durham, North Carolina 27708, USA A. Beretvas Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Bhatti The Rockefeller University, New York, New York 10065, USA M. Binkley¹¹1Deceased Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Bisello

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy I. Bizjak

^{h h}

University College London, London WC1E 6BT, United Kingdom K.R. Bland Baylor University, Waco, Texas 76798, USA B. Blumenfeld The Johns Hopkins University, Baltimore, Maryland 21218, USA A. Bocci Duke University, Durham, North Carolina 27708, USA A. Bodek University of Rochester, Rochester, New York 14627, USA D. Bortoletto Purdue University, West Lafayette, Indiana 47907, USA J. Boudreau University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA A. Boveia Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA B. Brau

^{a}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA L. Brigliadori

^{a a}

Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy A. Brisuda Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia C. Bromberg Michigan State University, East Lansing, Michigan 48824, USA E. Brucken Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland M. Bucciantonio

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy J. Budagov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia H.S. Budd University of Rochester, Rochester, New York 14627, USA S. Budd University of Illinois, Urbana, Illinois 61801, USA K. Burkett Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA G. Busetto

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy P. Bussey Glasgow University, Glasgow G12 8QQ, United Kingdom A. Buzatu Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 C. Calancha Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain S. Camarda Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain M. Campanelli Michigan State University, East Lansing, Michigan 48824, USA M. Campbell University of Michigan, Ann Arbor, Michigan 48109, USA F. Canelli

^{11}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA B. Carls University of Illinois, Urbana, Illinois 61801, USA D. Carlsmith University of Wisconsin, Madison, Wisconsin 53706, USA R. Carosi Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy S. Carrillo

^{k}

University of Florida, Gainesville, Florida 32611, USA S. Carron Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA B. Casal Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain M. Casarsa Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Castro

^{a a}

Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy P. Catastini Harvard University, Cambridge, Massachusetts 02138, USA D. Cauz Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy V. Cavaliere University of Illinois, Urbana, Illinois 61801, USA M. Cavalli-Sforza Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain A. Cerri

^{f}

Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA L. Cerrito

^{q}

University College London, London WC1E 6BT, United Kingdom Y.C. Chen Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China M. Chertok University of California, Davis, Davis, California 95616, USA G. Chiarelli Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy G. Chlachidze Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA F. Chlebana Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA K. Cho Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea D. Chokheli Joint Institute for Nuclear Research, RU-141980 Dubna, Russia J.P. Chou Harvard University, Cambridge, Massachusetts 02138, USA W.H. Chung University of Wisconsin, Madison, Wisconsin 53706, USA Y.S. Chung University of Rochester, Rochester, New York 14627, USA C.I. Ciobanu LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France M.A. Ciocci

^{d d}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy A. Clark University of Geneva, CH-1211 Geneva 4, Switzerland C. Clarke Wayne State University, Detroit, Michigan 48201, USA G. Compostella

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy M.E. Convery Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J. Conway University of California, Davis, Davis, California 95616, USA M.Corbo LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France M. Cordelli Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy C.A. Cox University of California, Davis, Davis, California 95616, USA D.J. Cox University of California, Davis, Davis, California 95616, USA F. Crescioli

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy C. Cuenca Almenar Yale University, New Haven, Connecticut 06520, USA J. Cuevas

^{w}

Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain R. Culbertson Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Dagenhart Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA N. d’Ascenzo

^{u}

LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France M. Datta Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA P. de Barbaro University of Rochester, Rochester, New York 14627, USA S. De Cecco Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,

^{f f}

Sapienza Università di Roma, I-00185 Roma, Italy G. De Lorenzo Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain M. Dell’Orso

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy C. Deluca Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain L. Demortier The Rockefeller University, New York, New York 10065, USA J. Deng

^{c}

Duke University, Durham, North Carolina 27708, USA M. Deninno Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy F. Devoto Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland M. d’Errico

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy A. Di Canto

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy B. Di Ruzza Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy J.R. Dittmann Baylor University, Waco, Texas 76798, USA M. D’Onofrio University of Liverpool, Liverpool L69 7ZE, United Kingdom S. Donati

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy P. Dong Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Dorigo Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy T. Dorigo Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy K. Ebina Waseda University, Tokyo 169, Japan A. Elagin Texas A&M University, College Station, Texas 77843, USA A. Eppig University of Michigan, Ann Arbor, Michigan 48109, USA R. Erbacher University of California, Davis, Davis, California 95616, USA D. Errede University of Illinois, Urbana, Illinois 61801, USA S. Errede University of Illinois, Urbana, Illinois 61801, USA N. Ershaidat

^{z}

LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France R. Eusebi Texas A&M University, College Station, Texas 77843, USA H.C. Fang Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA S. Farrington University of Oxford, Oxford OX1 3RH, United Kingdom M. Feindt Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany J.P. Fernandez Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain C. Ferrazza

^{e e}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy R. Field University of Florida, Gainesville, Florida 32611, USA G. Flanagan

^{s}

Purdue University, West Lafayette, Indiana 47907, USA R. Forrest University of California, Davis, Davis, California 95616, USA M.J. Frank Baylor University, Waco, Texas 76798, USA M. Franklin Harvard University, Cambridge, Massachusetts 02138, USA J.C. Freeman Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA Y. Funakoshi Waseda University, Tokyo 169, Japan I. Furic University of Florida, Gainesville, Florida 32611, USA M. Gallinaro The Rockefeller University, New York, New York 10065, USA J. Galyardt Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA J.E. Garcia University of Geneva, CH-1211 Geneva 4, Switzerland A.F. Garfinkel Purdue University, West Lafayette, Indiana 47907, USA P. Garosi

^{d d}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy H. Gerberich University of Illinois, Urbana, Illinois 61801, USA E. Gerchtein Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Giagu

^{f f}

Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,

^{f f}

Sapienza Università di Roma, I-00185 Roma, Italy V. Giakoumopoulou University of Athens, 157 71 Athens, Greece P. Giannetti Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy K. Gibson University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA C.M. Ginsburg Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA N. Giokaris University of Athens, 157 71 Athens, Greece P. Giromini Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy M. Giunta Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy G. Giurgiu The Johns Hopkins University, Baltimore, Maryland 21218, USA V. Glagolev Joint Institute for Nuclear Research, RU-141980 Dubna, Russia D. Glenzinski Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Gold University of New Mexico, Albuquerque, New Mexico 87131, USA D. Goldin Texas A&M University, College Station, Texas 77843, USA N. Goldschmidt University of Florida, Gainesville, Florida 32611, USA A. Golossanov Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA G. Gomez Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain G. Gomez-Ceballos Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA M. Goncharov Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA O. González Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain I. Gorelov University of New Mexico, Albuquerque, New Mexico 87131, USA A.T. Goshaw Duke University, Durham, North Carolina 27708, USA K. Goulianos The Rockefeller University, New York, New York 10065, USA S. Grinstein Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain C. Grosso-Pilcher Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA R.C. Group

^{55}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J. Guimaraes da Costa Harvard University, Cambridge, Massachusetts 02138, USA Z. Gunay-Unalan Michigan State University, East Lansing, Michigan 48824, USA C. Haber Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA S.R. Hahn Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA E. Halkiadakis Rutgers University, Piscataway, New Jersey 08855, USA A. Hamaguchi Osaka City University, Osaka 588, Japan J.Y. Han University of Rochester, Rochester, New York 14627, USA F. Happacher Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy K. Hara University of Tsukuba, Tsukuba, Ibaraki 305, Japan D. Hare Rutgers University, Piscataway, New Jersey 08855, USA M. Hare Tufts University, Medford, Massachusetts 02155, USA R.F. Harr Wayne State University, Detroit, Michigan 48201, USA K. Hatakeyama Baylor University, Waco, Texas 76798, USA C. Hays University of Oxford, Oxford OX1 3RH, United Kingdom M. Heck Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany J. Heinrich University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA M. Herndon University of Wisconsin, Madison, Wisconsin 53706, USA S. Hewamanage Baylor University, Waco, Texas 76798, USA D. Hidas Rutgers University, Piscataway, New Jersey 08855, USA A. Hocker Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA W. Hopkins

^{g}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Horn Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany S. Hou Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China R.E. Hughes The Ohio State University, Columbus, Ohio 43210, USA M. Hurwitz Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA M. Huschle Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany U. Husemann Yale University, New Haven, Connecticut 06520, USA N. Hussain Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 M. Hussein Michigan State University, East Lansing, Michigan 48824, USA J. Huston Michigan State University, East Lansing, Michigan 48824, USA G. Introzzi Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy M. Iori

^{f f}

Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,

^{f f}

Sapienza Università di Roma, I-00185 Roma, Italy A. Ivanov

^{o}

University of California, Davis, Davis, California 95616, USA E. James Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Jang Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA B. Jayatilaka Duke University, Durham, North Carolina 27708, USA E.J. Jeon Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea M.K. Jha Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy S. Jindariani Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA W. Johnson University of California, Davis, Davis, California 95616, USA M. Jones Purdue University, West Lafayette, Indiana 47907, USA K.K. Joo Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea S.Y. Jun Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA T.R. Junk Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA T. Kamon Texas A&M University, College Station, Texas 77843, USA P.E. Karchin Wayne State University, Detroit, Michigan 48201, USA A. Kasmi Baylor University, Waco, Texas 76798, USA Y. Kato

^{n}

Osaka City University, Osaka 588, Japan W. Ketchum Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA J. Keung University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA V. Khotilovich Texas A&M University, College Station, Texas 77843, USA B. Kilminster Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D.H. Kim Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea H.S. Kim Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea H.W. Kim Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea J.E. Kim Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea M.J. Kim Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy S.B. Kim Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea S.H. Kim University of Tsukuba, Tsukuba, Ibaraki 305, Japan Y.K. Kim Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA N. Kimura Waseda University, Tokyo 169, Japan M. Kirby Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Klimenko University of Florida, Gainesville, Florida 32611, USA K. Kondo Waseda University, Tokyo 169, Japan D.J. Kong Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea J. Konigsberg University of Florida, Gainesville, Florida 32611, USA A.V. Kotwal Duke University, Durham, North Carolina 27708, USA M. Kreps

^{i i}

Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany J. Kroll University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA D. Krop Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA N. Krumnack

^{l}

Baylor University, Waco, Texas 76798, USA M. Kruse Duke University, Durham, North Carolina 27708, USA V. Krutelyov

^{d}

Texas A&M University, College Station, Texas 77843, USA T. Kuhr Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany M. Kurata University of Tsukuba, Tsukuba, Ibaraki 305, Japan S. Kwang Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA A.T. Laasanen Purdue University, West Lafayette, Indiana 47907, USA S. Lami Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy S. Lammel Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Lancaster University College London, London WC1E 6BT, United Kingdom R.L. Lander University of California, Davis, Davis, California 95616, USA K. Lannon

^{v}

The Ohio State University, Columbus, Ohio 43210, USA A. Lath Rutgers University, Piscataway, New Jersey 08855, USA G. Latino

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy T. LeCompte Argonne National Laboratory, Argonne, Illinois 60439, USA E. Lee Texas A&M University, College Station, Texas 77843, USA H.S. Lee Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA J.S. Lee Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea S.W. Lee

^{x}

Texas A&M University, College Station, Texas 77843, USA S. Leo

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy S. Leone Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy J.D. Lewis Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Limosani

^{r}

Duke University, Durham, North Carolina 27708, USA C.-J. Lin Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA J. Linacre University of Oxford, Oxford OX1 3RH, United Kingdom M. Lindgren Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA E. Lipeles University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA A. Lister University of Geneva, CH-1211 Geneva 4, Switzerland D.O. Litvintsev Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA C. Liu University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA Q. Liu Purdue University, West Lafayette, Indiana 47907, USA T. Liu Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Lockwitz Yale University, New Haven, Connecticut 06520, USA A. Loginov Yale University, New Haven, Connecticut 06520, USA D. Lucchesi

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy J. Lueck Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany P. Lujan Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA P. Lukens Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA G. Lungu The Rockefeller University, New York, New York 10065, USA J. Lys Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA R. Lysak Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia R. Madrak Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA K. Maeshima Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA K. Makhoul Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA S. Malik The Rockefeller University, New York, New York 10065, USA G. Manca

^{b}

University of Liverpool, Liverpool L69 7ZE, United Kingdom A. Manousakis-Katsikakis University of Athens, 157 71 Athens, Greece F. Margaroli Purdue University, West Lafayette, Indiana 47907, USA C. Marino Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany M. Martínez Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain R. Martínez-Ballarín Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain P. Mastrandrea Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,

^{f f}

Sapienza Università di Roma, I-00185 Roma, Italy M.E. Mattson Wayne State University, Detroit, Michigan 48201, USA P. Mazzanti Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy K.S. McFarland University of Rochester, Rochester, New York 14627, USA P. McIntyre Texas A&M University, College Station, Texas 77843, USA R. McNulty

^{i}

University of Liverpool, Liverpool L69 7ZE, United Kingdom A. Mehta University of Liverpool, Liverpool L69 7ZE, United Kingdom P. Mehtala Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland A. Menzione Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy C. Mesropian The Rockefeller University, New York, New York 10065, USA T. Miao Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Mietlicki University of Michigan, Ann Arbor, Michigan 48109, USA A. Mitra Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China H. Miyake University of Tsukuba, Tsukuba, Ibaraki 305, Japan S. Moed Harvard University, Cambridge, Massachusetts 02138, USA N. Moggi Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy M.N. Mondragon

^{k}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA C.S. Moon Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea R. Moore Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M.J. Morello Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J. Morlock Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany P. Movilla Fernandez Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Mukherjee Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA Th. Muller Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany P. Murat Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Mussini

^{a a}

Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy J. Nachtman

^{m}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA Y. Nagai University of Tsukuba, Tsukuba, Ibaraki 305, Japan J. Naganoma Waseda University, Tokyo 169, Japan I. Nakano Okayama University, Okayama 700-8530, Japan A. Napier Tufts University, Medford, Massachusetts 02155, USA J. Nett Texas A&M University, College Station, Texas 77843, USA C. Neu University of Virginia, Charlottesville, VA 22906, USA M.S. Neubauer University of Illinois, Urbana, Illinois 61801, USA J. Nielsen

^{e}

Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA L. Nodulman Argonne National Laboratory, Argonne, Illinois 60439, USA O. Norniella University of Illinois, Urbana, Illinois 61801, USA E. Nurse University College London, London WC1E 6BT, United Kingdom L. Oakes University of Oxford, Oxford OX1 3RH, United Kingdom S.H. Oh Duke University, Durham, North Carolina 27708, USA Y.D. Oh Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea I. Oksuzian University of Virginia, Charlottesville, VA 22906, USA T. Okusawa Osaka City University, Osaka 588, Japan R. Orava Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland L. Ortolan Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain S. Pagan Griso

^{b b}

Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy C. Pagliarone Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy E. Palencia

^{f}

Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain V. Papadimitriou Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A.A. Paramonov Argonne National Laboratory, Argonne, Illinois 60439, USA J. Patrick Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA G. Pauletta

^{g g}

Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy M. Paulini Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA C. Paus Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA D.E. Pellett University of California, Davis, Davis, California 95616, USA A. Penzo Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy T.J. Phillips Duke University, Durham, North Carolina 27708, USA G. Piacentino Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy E. Pianori University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA J. Pilot The Ohio State University, Columbus, Ohio 43210, USA K. Pitts University of Illinois, Urbana, Illinois 61801, USA C. Plager University of California, Los Angeles, Los Angeles, California 90024, USA L. Pondrom University of Wisconsin, Madison, Wisconsin 53706, USA K. Potamianos Purdue University, West Lafayette, Indiana 47907, USA O. Poukhov^†^†footnotemark: Joint Institute for Nuclear Research, RU-141980 Dubna, Russia F. Prokoshin

^{y}

Joint Institute for Nuclear Research, RU-141980 Dubna, Russia A. Pronko Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA F. Ptohos

^{h}

Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy E. Pueschel Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA G. Punzi

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy J. Pursley University of Wisconsin, Madison, Wisconsin 53706, USA A. Rahaman University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA V. Ramakrishnan University of Wisconsin, Madison, Wisconsin 53706, USA N. Ranjan Purdue University, West Lafayette, Indiana 47907, USA I. Redondo Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain P. Renton University of Oxford, Oxford OX1 3RH, United Kingdom M. Rescigno Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1,

^{f f}

Sapienza Università di Roma, I-00185 Roma, Italy T. Riddick University College London, London WC1E 6BT, United Kingdom F. Rimondi

^{a a}

Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy L. Ristori

^{44}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Robson Glasgow University, Glasgow G12 8QQ, United Kingdom T. Rodrigo Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain T. Rodriguez University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA E. Rogers University of Illinois, Urbana, Illinois 61801, USA S. Rolli Tufts University, Medford, Massachusetts 02155, USA R. Roser Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Rossi Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy F. Rubbo Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA F. Ruffini

^{d d}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy A. Ruiz Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain J. Russ Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA V. Rusu Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Safonov Texas A&M University, College Station, Texas 77843, USA W.K. Sakumoto University of Rochester, Rochester, New York 14627, USA Y. Sakurai Waseda University, Tokyo 169, Japan L. Santi

^{g g}

Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy L. Sartori Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy K. Sato University of Tsukuba, Tsukuba, Ibaraki 305, Japan V. Saveliev

^{u}

LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France A. Savoy-Navarro LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France P. Schlabach Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Schmidt Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany E.E. Schmidt Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M.P. Schmidt^†^†footnotemark: Yale University, New Haven, Connecticut 06520, USA M. Schmitt Northwestern University, Evanston, Illinois 60208, USA T. Schwarz University of California, Davis, Davis, California 95616, USA L. Scodellaro Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain A. Scribano

^{d d}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy F. Scuri Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy A. Sedov Purdue University, West Lafayette, Indiana 47907, USA S. Seidel University of New Mexico, Albuquerque, New Mexico 87131, USA Y. Seiya Osaka City University, Osaka 588, Japan A. Semenov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia F. Sforza

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy A. Sfyrla University of Illinois, Urbana, Illinois 61801, USA S.Z. Shalhout University of California, Davis, Davis, California 95616, USA T. Shears University of Liverpool, Liverpool L69 7ZE, United Kingdom P.F. Shepard University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA M. Shimojima

^{t}

University of Tsukuba, Tsukuba, Ibaraki 305, Japan S. Shiraishi Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA M. Shochet Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA I. Shreyber Institution for Theoretical and Experimental Physics, ITEP, Moscow 117259, Russia A. Simonenko Joint Institute for Nuclear Research, RU-141980 Dubna, Russia P. Sinervo Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 A. Sissakian^†^†footnotemark: Joint Institute for Nuclear Research, RU-141980 Dubna, Russia K. Sliwa Tufts University, Medford, Massachusetts 02155, USA J.R. Smith University of California, Davis, Davis, California 95616, USA F.D. Snider Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Soha Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Somalwar Rutgers University, Piscataway, New Jersey 08855, USA V. Sorin Institut de Fisica d’Altes Energies, ICREA, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain P. Squillacioti Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Stancari Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA M. Stanitzki Yale University, New Haven, Connecticut 06520, USA R. St. Denis Glasgow University, Glasgow G12 8QQ, United Kingdom B. Stelzer Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 O. Stelzer-Chilton Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 D. Stentz Northwestern University, Evanston, Illinois 60208, USA J. Strologas University of New Mexico, Albuquerque, New Mexico 87131, USA G.L. Strycker University of Michigan, Ann Arbor, Michigan 48109, USA Y. Sudo University of Tsukuba, Tsukuba, Ibaraki 305, Japan A. Sukhanov University of Florida, Gainesville, Florida 32611, USA I. Suslov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia K. Takemasa University of Tsukuba, Tsukuba, Ibaraki 305, Japan Y. Takeuchi University of Tsukuba, Tsukuba, Ibaraki 305, Japan J. Tang Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA M. Tecchio University of Michigan, Ann Arbor, Michigan 48109, USA P.K. Teng Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China J. Thom

^{g}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J. Thome Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA G.A. Thompson University of Illinois, Urbana, Illinois 61801, USA E. Thomson University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA P. Ttito-Guzmán Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain S. Tkaczyk Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA D. Toback Texas A&M University, College Station, Texas 77843, USA S. Tokar Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia K. Tollefson Michigan State University, East Lansing, Michigan 48824, USA T. Tomura University of Tsukuba, Tsukuba, Ibaraki 305, Japan D. Tonelli Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Torre Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy D. Torretta Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA P. Totaro Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento,

^{b b}

University of Padova, I-35131 Padova, Italy M. Trovato

^{e e}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy Y. Tu University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA F. Ukegawa University of Tsukuba, Tsukuba, Ibaraki 305, Japan S. Uozumi Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea A. Varganov University of Michigan, Ann Arbor, Michigan 48109, USA F. Vázquez

^{k}

University of Florida, Gainesville, Florida 32611, USA G. Velev Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA C. Vellidis University of Athens, 157 71 Athens, Greece M. Vidal Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain I. Vila Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain R. Vilar Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain J. Vizán Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain M. Vogel University of New Mexico, Albuquerque, New Mexico 87131, USA G. Volpi

^{c c}

Istituto Nazionale di Fisica Nucleare Pisa,

^{c c}

University of Pisa,

^{d d}

University of Siena and

^{e e}

Scuola Normale Superiore, I-56127 Pisa, Italy P. Wagner University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA R.L. Wagner Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA T. Wakisaka Osaka City University, Osaka 588, Japan R. Wallny University of California, Los Angeles, Los Angeles, California 90024, USA S.M. Wang Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China A. Warburton Institute of Particle Physics: McGill University, Montréal, Québec, Canada H3A 2T8; Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6; University of Toronto, Toronto, Ontario, Canada M5S 1A7; and TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 D. Waters University College London, London WC1E 6BT, United Kingdom M. Weinberger Texas A&M University, College Station, Texas 77843, USA W.C. Wester III Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA B. Whitehouse Tufts University, Medford, Massachusetts 02155, USA D. Whiteson

^{c}

University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA A.B. Wicklund Argonne National Laboratory, Argonne, Illinois 60439, USA E. Wicklund Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Wilbur Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA F. Wick Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany H.H. Williams University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA J.S. Wilson The Ohio State University, Columbus, Ohio 43210, USA P. Wilson Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA B.L. Winer The Ohio State University, Columbus, Ohio 43210, USA P. Wittich

^{g}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA S. Wolbers Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA H. Wolfe The Ohio State University, Columbus, Ohio 43210, USA T. Wright University of Michigan, Ann Arbor, Michigan 48109, USA X. Wu University of Geneva, CH-1211 Geneva 4, Switzerland Z. Wu Baylor University, Waco, Texas 76798, USA K. Yamamoto Osaka City University, Osaka 588, Japan J. Yamaoka Duke University, Durham, North Carolina 27708, USA T. Yang Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA U.K. Yang

^{p}

Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA Y.C. Yang Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea W.-M. Yao Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA G.P. Yeh Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA K. Yi

^{m}

Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J. Yoh Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA K. Yorita Waseda University, Tokyo 169, Japan T. Yoshida

^{j}

Osaka City University, Osaka 588, Japan G.B. Yu Duke University, Durham, North Carolina 27708, USA I. Yu Center for High Energy Physics: Kyungpook National University, Daegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; Sungkyunkwan University, Suwon 440-746, Korea; Korea Institute of Science and Technology Information, Daejeon 305-806, Korea; Chonnam National University, Gwangju 500-757, Korea; Chonbuk National University, Jeonju 561-756, Korea S.S. Yu Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA J.C. Yun Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA A. Zanetti Istituto Nazionale di Fisica Nucleare Trieste/Udine, I-34100 Trieste,

^{g g}

University of Udine, I-33100 Udine, Italy Y. Zeng Duke University, Durham, North Carolina 27708, USA S. Zucchelli

^{a a}

Istituto Nazionale di Fisica Nucleare Bologna,

^{a a}

University of Bologna, I-40127 Bologna, Italy

July 13, 2019

Abstract

We present a study of $B_{s}^{0}$ decays to the CP-odd final state $J / ψ f_{0} (980)$ with $J / ψ \to μ^{+} μ^{-}$ and $f_{0} (980) \to π^{+} π^{-}$ . Using $p ¯ p$ collision data with an integrated luminosity of $3.8$ $f b^{- 1}$ collected by the CDF II detector at the Tevatron we measure a $B_{s}^{0}$ lifetime of $τ (B_{s}^{0} \to J / ψ f_{0} (980)) = {1.70}_{- 0.11}^{+ 0.12} (s t a t) \pm 0.03 (s y s t) p s$ . This is the first measurement of the $B_{s}^{0}$ lifetime in a decay to a CP eigenstate and corresponds in the standard model to the lifetime of the heavy $B_{s}^{0}$ eigenstate. We also measure the product of branching fractions of $B_{s}^{0} \to J / ψ f_{0} (980)$ and $f_{0} (980) \to π^{+} π^{-}$ relative to the product of branching fractions of $B_{s}^{0} \to J / ψ ϕ$ and $ϕ \to K^{+} K^{-}$ to be $R_{f_{0} / ϕ} = 0.257 \pm 0.020 (s t a t) \pm 0.014 (s y s t)$ , which is the most precise determination of this quantity to date.

pacs:

13.25.Hw, 14.40.Nd, 12.15.Nf

CDF Collaboration²²2With visitors from $^{a}$ University of MA Amherst, Amherst, MA 01003, USA, $^{b}$ Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari, 09042 Monserrato (Cagliari), Italy, $^{c}$ University of CA Irvine, Irvine, CA 92697, USA, $^{d}$ University of CA Santa Barbara, Santa Barbara, CA 93106, USA, $^{e}$ University of CA Santa Cruz, Santa Cruz, CA 95064, USA, $^{f}$ CERN,CH-1211 Geneva, Switzerland, $^{g}$ Cornell University, Ithaca, NY 14853, USA, $^{h}$ University of Cyprus, Nicosia CY-1678, Cyprus, $^{i}$ University College Dublin, Dublin 4, Ireland, $^{j}$ University of Fukui, Fukui City, Fukui Prefecture, Japan 910-0017, $^{k}$ Universidad Iberoamericana, Mexico D.F., Mexico, $^{l}$ Iowa State University, Ames, IA 50011, USA, $^{m}$ University of Iowa, Iowa City, IA 52242, USA, $^{n}$ Kinki University, Higashi-Osaka City, Japan 577-8502, $^{o}$ Kansas State University, Manhattan, KS 66506, USA, $^{p}$ University of Manchester, Manchester M13 9PL, United Kingdom, $^{q}$ Queen Mary, University of London, London, E1 4NS, United Kingdom, $^{r}$ University of Melbourne, Victoria 3010, Australia, $^{s}$ Muons, Inc., Batavia, IL 60510, USA, $^{t}$ Nagasaki Institute of Applied Science, Nagasaki, Japan, $^{u}$ National Research Nuclear University, Moscow, Russia, $^{v}$ University of Notre Dame, Notre Dame, IN 46556, USA, $^{w}$ Universidad de Oviedo, E-33007 Oviedo, Spain, $^{x}$ Texas Tech University, Lubbock, TX 79609, USA, $^{y}$ Universidad Tecnica Federico Santa Maria, 110v Valparaiso, Chile, $^{z}$ Yarmouk University, Irbid 211-63, Jordan, $^{h h}$ On leave from J. Stefan Institute, Ljubljana, Slovenia, $^{i i}$ University of Warwick, Coventry CV4 7AL, United Kingdom,

I Introduction

In the standard model, the mass and flavor eigenstates of the $B_{s}^{0}$ meson are not identical. This gives rise to particle – anti-particle oscillations Gay:2001ra (), which proceed in the standard model through second order weak interaction processes, and whose phenomenology depends on the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix. The time $(t)$ evolution of $B_{s}^{0}$ mesons is approximately governed by the Schrödinger equation

i \frac{d}{d t} (\begin{matrix} | B_{s}^{0} (t) ⟩ | {¯ B}_{s}^{0} (t) ⟩ \end{matrix}) = ({^M}^{s} - \frac{i}{2}^Γ^{s}) (\begin{matrix} | B_{s}^{0} (t) ⟩ | {¯ B}_{s}^{0} (t) ⟩ \end{matrix}),

(1)

where ${^M}^{s}$ and ${^Γ}^{s}$ are mass and decay rate symmetric $2 \times 2$ matrices. Diagonalization of ${^M}^{s} - \frac{i}{2} {^Γ}^{s}$ leads to mass eigenstates

	$\| B_{s L}^{0} ⟩$	$=$	$p \| B_{s}^{0} ⟩ + q \| {¯ B}_{s}^{0} ⟩,$		(2)
	$\| B_{s H}^{0} ⟩$	$=$	$p \| B_{s}^{0} ⟩ - q \| {¯ B}_{s}^{0} ⟩,$		(3)

with distinct masses ( $M_{s}^{L}, M_{s}^{H}$ ) and distinct decay rates ( $Γ_{s}^{L}, Γ_{s}^{H}$ ), where $p$ and $q$ are complex numbers satisfying $| p |^{2} + | q |^{2} = 1$ . An important feature of the $B_{s}^{0}$ system is the non-zero matrix element $Γ_{12}^{s}$ representing the partial width of $B_{s}^{0}$ and ${¯ B}_{s}^{0}$ decays to common final states which translates into a non-zero decay width difference $Δ Γ_{s}$ of the two mass eigenstates through the relation

Δ Γ_{s}

=

Γ_{s}^{L} - Γ_{s}^{H} = 2 | Γ_{12}^{s} | cos ϕ_{s},

(4)

where $ϕ_{s} = arg (- M_{12}^{s} / Γ_{12}^{s})$ . The phase $ϕ_{s}$ describes CP violation in $B_{s}^{0}$ mixing. In the standard model $ϕ_{s}$ is predicted to be ${0.22}^{\circ} \pm {0.06}^{\circ}$ Lenz:2006hd (); Nierste:2011ti (). The small value of the phase $ϕ_{s}$ causes the mass and CP eigenstates to coincide to a good approximation. Thus the measurement of the lifetime in a CP eigenstate provides directly the lifetime of the corresponding mass eigenstate. If new physics is present, it could enhance $ϕ_{s}$ to large values, a scenario which is not excluded by current experimental constraints. In such a case the correspondence between mass and CP eigenstates does not hold anymore and the measured lifetime will correspond to the weighted average of the lifetimes of the two mass eigenstates with weights dependent on the size of the CP violating phase $ϕ_{s}$ Dunietz:2000cr (). Thus a measurement of the $B_{s}^{0}$ lifetime in a final state which is a CP eigenstate provides, in combination with other measurements, valuable information on the decay width difference $Δ Γ_{s}$ and the CP violation in $B_{s}^{0}$ mixing.

One of the most powerful measurements to constrain a new physics contribution to the phase $ϕ_{s}$ is the measurement of CP violation in the decay $B_{s}^{0} \to J / ψ ϕ$ with $ϕ \to K^{+} K^{-}$ . The decay $B_{s}^{0} \to J / ψ ϕ$ has a mixture of the CP-even and -odd components in the final state and an angular analysis is needed to separate them Dighe:1995pd (). In the standard model, CP violation in the decay $B_{s}^{0} \to J / ψ ϕ$ is given by $β_{s} = arg [(- V_{t s} V_{t b}^{*}) / (V_{c s} V_{c b}^{*})]$ . New physics effects in $B_{s}^{0}$ mixing would shift $ϕ_{s}$ and $- 2 β_{s}$ from the standard model value by the same amount. A sufficiently copious $B_{s}^{0} \to J / ψ f_{0}$ signal with $f_{0} \to π^{+} π^{-}$ , where $f_{0}$ stands for $f_{0} (980)$ , and $B_{s}^{0}$ flavor identified at production can be used to measure $β_{s}$ without the need of an angular analysis Stone:2009hd () as $J / ψ f_{0}$ is a pure CP-odd final state. Since the $B_{s}^{0}$ is a spin 0 particle and the decay products $J / ψ$ and $f_{0}$ have quantum numbers $J^{P C} = 1^{- -}$ and $0^{+ +}$ , respectively, the final state has an orbital angular momentum of $L = 1$ leading to a CP eigenvalue of $(- 1)^{L} = - 1$ . Further interest in the decay $B_{s}^{0} \to J / ψ f_{0}$ arises from its possible contribution to an $S$ -wave component in the $B_{s}^{0} \to J / ψ K^{+} K^{-}$ decay if the $f_{0}$ decays to $K^{+} K^{-}$ . This contribution could help to resolve an ambiguity in the $Δ Γ_{s}$ and $β_{s}$ values determined in the $B_{s}^{0} \to J / ψ ϕ$ analyses. Because it was neglected in the first tagged $B_{s}^{0} \to J / ψ ϕ$ results Aaltonen:2007he (); Abazov:2008fj (), each of which showed an approximately 1.5 $σ$ deviation from the standard model, it was argued that the omission may significantly bias the results Stone:2008ak (); Stone:2010dp (). However, using the formalism in Ref. Azfar:2010nz (), the latest preliminary CDF measurement beta_s () has shown that the $S$ -wave interference effect is negligible at the current level of precision.

In Refs. Lenz:2006hd (); Nierste:2011ti () the decay width difference in the standard model is predicted to be $Δ Γ_{s}^{S M} = (0.087 \pm 0.021)$ ps $^{- 1}$ and the ratio of the average $B_{s}^{0}$ lifetime, $τ_{s} = 2 / (Γ_{s}^{L} + Γ_{s}^{H})$ , to the $B^{0}$ lifetime, $τ_{d}$ , to be $0.996 < τ_{s} / τ_{d} < 1$ . Using these predictions in the relations

	$Γ_{s}^{H}$	$=$	$\frac{1}{τ_{s}^{H}} = Γ_{s} - \frac{1}{2} Δ Γ_{s},$		(5)
	$Γ_{L}^{s}$	$=$	$\frac{1}{τ_{s}^{L}} = Γ_{s} + \frac{1}{2} Δ Γ_{s},$		(6)

where $Γ_{s} = 1 / τ_{s}$ , together with the world average $B^{0}$ lifetime, $τ_{d} = (1.525 \pm 0.009)$ ps Nakamura:2010zzi (), we find the theoretically-derived values $τ_{s}^{H} = (1.630 \pm 0.030)$ ps and $τ_{s}^{L} = (1.427 \pm 0.023)$ ps.

While no direct measurements of $B_{s}^{0}$ lifetimes in decays to pure CP eigenstates are available, various experimental results allow for the determination of the lifetimes of the two mass eigenstates. Measurements sensitive to these lifetimes are the angular analysis of $B_{s}^{0} \to J / ψ ϕ$ decays and the branching fraction of $B_{s}^{0} \to D_{s}^{(*) +} D_{s}^{(*) -}$ , which can be complemented by measurements of the $B_{s}^{0}$ lifetime in flavor specific final states. The combination of available measurements yields $τ_{s}^{H} = (1.544 \pm 0.041)$ ps and $τ_{s}^{L} = ({1.407}_{- 0.026}^{+ 0.028})$ ps Asner:2010qj (). From CDF measurements we can infer the two lifetimes from the result of the angular analysis of $B_{s}^{0} \to J / ψ ϕ$ decays. The latest preliminary result beta_s (), that is not yet included in the above average, yields $τ_{s}^{H} = (1.622 \pm 0.068)$ ps and $τ_{s}^{L} = (1.446 \pm 0.035)$ ps assuming standard model CP violation.

Compared to measurements using $B_{s}^{0} \to J / ψ ϕ$ decays, lifetime and future CP violation measurements in the $B_{s}^{0} \to J / ψ f_{0}$ decay suffer from a lower branching fraction. Based on a comparison to $D_{s}^{+}$ meson decays Ref. Stone:2008ak () makes a prediction for the branching fraction of $B_{s}^{0} \to J / ψ f_{0}$ decay relative to the $B_{s}^{0} \to J / ψ ϕ$ decay,

R_{f_{0} / ϕ} = \frac{B (B_{s}^{0} \to J / ψ f_{0})}{B (B_{s}^{0} \to J / ψ ϕ)} \frac{B (f_{0} \to π^{+} π^{-})}{B (ϕ \to K^{+} K^{-})},

(7)

to be approximately 0.2. The CLEO experiment estimates $R_{f_{0} / ϕ} = 0.42 \pm 0.11$ from a measurement of semileptonic $D_{s}^{+}$ decays Ecklund:2009fia (). A theoretical prediction based on QCD factorization yields a range of $R_{f_{0} / ϕ}$ between $0.2$ and $0.5$ Leitner:2010fq (). With the world average branching fraction for the $B_{s}^{0} \to J / ψ ϕ$ decay of $(1.3 \pm 0.4) \times 10^{- 3}$ and the branching fraction of $f_{0} \to π^{+} π^{-}$ in the region between 0.5–0.8, predictions of $B (B_{s}^{0} \to J / ψ f_{0})$ Colangelo:2010bg (); Colangelo:2010wg () translate into a wide range of $R_{f_{0} / ϕ}$ values of approximately 0.1–0.5.

The first experimental search was performed by the Belle experiment Louvot:2010es (). Their preliminary result did not yield a signal and they extract an upper limit on the branching fraction of $B (B_{s}^{0} \to J / ψ f_{0}) B (f_{0} \to π^{+} π^{-}) < 1.63 \times 10^{- 4} a t 90 % C . L$ . Recently the LHCb experiment reported the first observation of the decay $B_{s}^{0} \to J / ψ f_{0}$ Aaij:2011fx () with a relative branching fraction of $R_{f_{0} / ϕ} = {0.252}_{- 0.032}^{+ 0.046} (s t a t)_{- 0.033}^{+ 0.027} (s y s t)$ . Shortly after the LHCb result was presented, the Belle collaboration announced their result of an updated analysis using 121.4 $f b^{- 1}$ of $Υ (5 S)$ data Li:2011pg (). They observe a significant $B_{s}^{0} \to J / ψ f_{0}$ signal and measure $B (B_{s}^{0} \to J / ψ f_{0}) B (f_{0} \to π^{+} π^{-}) = ({1.16}_{- 0.19}^{+ 0.31}^{+ 0.15}_{- 0.17}^{+ 0.26}_{- 0. 18}) \times 10^{- 4}$ , where the first uncertainty is statistical, the second systematic, and the third one is an uncertainty on the number of produced $B_{s}^{(*) 0} {¯ B}_{s}^{(*) 0}$ pairs. Using their preliminary measurement of the $B_{s}^{0} \to J / ψ ϕ$ branching fraction Louvot:2009xg (), and assuming that the uncertainty on the number of produced $B_{s}^{(*) 0} {¯ B}_{s}^{(*) 0}$ pairs is fully correlated for the two measurements, this translates into $R_{f_{0} / ϕ} = {0.206}_{- 0.034}^{+ 0.055} (s t a t) \pm 0.052 (s y s t)$ . A preliminary measurement of the D0 experiment yields $R_{f_{0} / ϕ} = 0.210 \pm 0.032 (s t a t) \pm 0.036 (s y s t)$ D0:6152 ().

In this paper we present a measurement of the ratio $R_{f_{0} / ϕ}$ of the branching fraction of the $B_{s}^{0} \to J / ψ f_{0}$ decay relative to the $B_{s}^{0} \to J / ψ ϕ$ decay and the first measurement of the $B_{s}^{0}$ lifetime in a decay to a pure CP eigenstate. We use data collected by the CDF II detector from February 2002 until October 2008. The data correspond to an integrated luminosity of $3.8 {fb}^{- 1}$ .

This paper is organized as follows: In Sec. II we describe the CDF II detector together with the online data selection, followed by the candidate selection in Sec. III. Section IV describes details of the measurement of the ratio $R_{f_{0} / ϕ}$ of branching fractions of the $B_{s}^{0} \to J / ψ f_{0}$ decay relative to the $B_{s}^{0} \to J / ψ ϕ$ decay while Sec. V discusses the lifetime measurement. We finish with a short discussion of the results and conclusions in Sec. VI.

Ii CDF II detector and trigger

Among the components of the CDF II detector Acosta:2004yw () the tracking and muon detection systems are most relevant for this analysis. The tracking system lies within a uniform, axial magnetic field of $1.4$ T strength. The inner tracking volume hosts 7 layers of double-sided silicon micro-strip detectors up to a radius of $28$ cm Hill:2004qb (). An additional layer of single-sided silicon is mounted directly on the beam-pipe at a radius of $1.5$ cm, providing an excellent resolution of the impact parameter $d_{0}$ , defined as the distance of closest approach of the track to the interaction point in the transverse plane. The silicon tracker provides a pseudorapidity coverage up to $| η | \leq 2.0$ . The remainder of the tracking volume up to a radius of $137$ cm is occupied by an open-cell drift chamber Affolder:2003ep (). The drift chamber provides up to 96 measurements along the track with half of them being axial and other half stereo. Tracks with $| η | \leq 1.0$ pass the full radial extent of the drift chamber. The integrated tracking system achieves a transverse momentum resolution of $σ (p_{T}) / p_{T}^{2} \approx 0.07 %$ (GeV $/ c$ ) $^{- 1}$ and an impact parameter resolution of $σ (d_{0}) \approx 35$ $μ m$ for tracks with a transverse momentum greater than 2 $G e V / c$ . The tracking system is surrounded by electromagnetic and hadronic calorimeters, which cover the full pseudorapidity range of the tracking system Balka:1987ty (); Bertolucci:1987zn (); Albrow:2001jw (); Apollinari:1998bg (). We detect muons in three sets of multi-wire drift chambers. The central muon detector has a pseudorapidity coverage of $| η | < 0.6$ Ascoli:1987av () and the calorimeters in front of it provide about 5.5 interaction lengths of material. The minimum transverse momentum to reach this set of muon chambers is about 1.4 $G e V / c$ . The second set of chambers covers the same range in $η$ , but is located behind an additional 60 cm of steel absorber, which corresponds to about 3 interaction lengths. It has a higher transverse momentum threshold of 2 $G e V / c$ , but provides a cleaner muon identification. The third set of muon detectors extends the coverage to a region of $0.6 < | η | < 1.0$ and is shielded by about 6 interaction lengths of material.

A three-level trigger system is used for the online event selection. The trigger component most important for this analysis is the extremely fast tracker (XFT) Thomson:2002xp (), which at the first level groups hits from the drift chamber into tracks in the plane transverse to the beamline. Candidate events containing $J / ψ \to μ^{+} μ^{-}$ decays are selected by a dimuon trigger Acosta:2004yw () which requires two tracks of opposite charge found by the XFT that match to track segments in the muon chambers and have a dimuon invariant mass in the range 2.7 to 4.0 GeV/ $c^{2}$ .

Iii Reconstruction and candidate selection

iii.1 Reconstruction

In the offline reconstruction we first combine two muon candidates of opposite charge to form a $J / ψ$ candidate. We consider all tracks that can be matched to a track segment in the muon detectors as muon candidates. The $J / ψ$ candidate is subject to a kinematic fit with a vertex constraint. We then combine the $J / ψ$ candidate with two other oppositely charged tracks that are assumed to be pions and have an invariant mass between 0.85 and 1.2 $G e V / c^{2}$ to form a $B_{s}^{0} \to J / ψ f_{0}$ candidate. In the final step a kinematic fit of the $B_{s}^{0} \to J / ψ f_{0}$ candidate is performed. In this fit we constrain all four tracks to originate from a common vertex, and the two muons forming the $J / ψ$ are constrained to have an invariant mass equal to the world average $J / ψ$ mass Nakamura:2010zzi (). In a similar way we also reconstruct $B_{s}^{0} \to J / ψ ϕ$ candidates using pairs of tracks of opposite charge assumed to be kaons and having an invariant mass between 1.009 and 1.029 $G e V / c^{2}$ . During the reconstruction we place minimal requirements on the track quality, the quality of the kinematic fit, and the transverse momentum of the $B_{s}^{0}$ candidate to ensure high quality measurements of properties for each candidate. For the branching fraction measurement we add a requirement which aims at removing a large fraction of short-lived background. We require the decay time of the $B_{s}^{0}$ candidate in its own rest frame, the proper decay time, to be larger than three times its uncertainty. This criterion is not imposed in the lifetime analysis since it would bias the lifetime distribution. The proper decay time is determined by the expression

t = \frac{L_{x y} \cdot m (B_{s}^{0})}{c \cdot p_{T}}

(8)

where $L_{x y}$ is the flight distance projected onto the $B_{s}^{0}$ momentum in the plane transverse to the beamline, $p_{T}$ is the transverse momentum of the given candidate, and $m (B_{s}^{0})$ is the reconstructed mass of the $B_{s}^{0}$ candidate. The uncertainty on the proper decay time $t$ is estimated for each candidate by propagating track parameter and primary vertex uncertainties into an uncertainty on $L_{x y}$ . The proper decay time resolution is typically of the order of 0.1 ps.

iii.2 Selection

The selection is performed using a neural network based on the neurobayes package Feindt:2006pm (); Feindt:2004aa (). The neural network combines several input variables to form a single output variable on which the selection is performed. The transformation from the multidimensional space of input variables to the single output variable is chosen during a training phase such that it maximizes the separation between signal and background distributions. For each of the two measurements presented in this paper we use a specialized neural network. For the training we need two sets of events with a known classification of signal or background. For the signal sample we use simulated events. We generate the kinematic distributions of $B_{s}^{0}$ mesons according to the measured $b$ -hadron momentum distribution. The decay of the generated $B_{s}^{0}$ particles into the $J / ψ f_{0}$ final state is simulated using the evtgen package Lange:2001uf (). Each event is passed through the standard CDF II detector simulation, based on the geant3 package Brun:1978fy (); Gerchtein:2003ba (). The simulated events are reconstructed with the same reconstruction software as real data events. The background sample is taken from data using candidates with the $J / ψ π^{+} π^{-}$ invariant mass above the $B_{s}^{0}$ signal peak, where only combinatorial background events contribute. Because the requirement on the proper decay time significance efficiently suppresses background events in the branching ratio measurement, we use an enlarged sideband region of 5.45 to 5.55 $G e V / c^{2}$ in this analysis, compared to an invariant mass range from 5.45 to 5.475 $G e V / c^{2}$ for the lifetime measurement.

For the branching fraction measurement, the inputs to the neural network, ordered by the importance of their contribution to the discrimination power, are the transverse momentum of the $f_{0}$ , the $χ^{2}$ of the kinematic fit of the $B_{s}^{0}$ candidate using information in the plane transverse to the beamline, the proper decay time of the $B_{s}^{0}$ candidate, the quality of the kinematic fit of the $B_{s}^{0}$ candidate, the helicity angle of the positive pion, the transverse momentum of the $B_{s}^{0}$ candidate, the quality of the kinematic fit of the two pions with a common vertex constraint, the helicity angle of the positive muon, and the quality of the kinematic fit of the two muons with common vertex constraint. The helicity angle of the muon (pion) is defined as the angle between the three momenta of the muon (pion) and $B_{s}^{0}$ candidate measured in the rest frame of the $J / ψ$ ( $f_{0}$ ). For the selection of $B_{s}^{0} \to J / ψ ϕ$ decays we use the same neural network without retraining and simply replace $f_{0}$ variables by $ϕ$ variables and pions by kaons.

For the lifetime measurement we modify the list of inputs by removing the proper decay time. We also do not use the helicity angles as they provide almost no additional separation power on the selected sample. Since we are not concerned about a precise efficiency determination for the lifetime measurement, we add the following inputs: the invariant mass of the two pions, the likelihood based identification information for muons Thesis:Giurgiu (), and the invariant mass of the muon pair. The muon identification is based on the matching of tracks from the tracking system to track segments in the muon system, energy deposition in the electromagnetic and hadronic calorimeters, and isolation of the track. The isolation is defined as the transverse momentum carried by the muon candidate over the scalar sum of transverse momenta of all tracks in a cone of $Δ R = \sqrt{(Δ ϕ)^{2} + (Δ η)^{2}} < 0.4$ , where $Δ ϕ$ ( $Δ η$ ) is the difference in azimuthal angle (pseudorapidity) of the muon candidate and the track. There is no significant change in the importance ordering of the inputs. The invariant mass of the pion pair becomes the second most important input, the likelihood based identification of the two muon candidates is ranked fourth and sixth in the importance list, and the muon pair invariant mass is the least important input.

For the branching fraction measurement we select the threshold on the neural network output by maximizing $ϵ / (2.5 + \sqrt{N_{b}})$ Punzi:2003bu (), where $ϵ$ is the reconstruction efficiency for $B_{s}^{0} \to J / ψ f_{0}$ decays and $N_{b}$ is the number of background events estimated from the $J / ψ π^{+} π^{-}$ mass sideband. The invariant mass distributions of selected $B_{s}^{0} \to J / ψ f_{0}$ and $B_{s}^{0} \to J / ψ ϕ$ candidates are shown in Figs. 1 and 2. A clear signal at around 5.36 $G e V / c^{2}$ is visible in both mass distributions.

Figure 1: The invariant mass distribution of $B_{s}^{0} \to J / ψ f_{0}$ candidates selected for the branching fraction measurement.

Figure 2: The invariant mass distribution of $B_{s}^{0} \to J / ψ ϕ$ candidates selected for the branching fraction measurement.

For the lifetime measurement we use simulated experiments to determine the optimal neural network output requirement. We select a value that minimizes the statistical uncertainty of the measured lifetime. We scan a wide range of neural network output values and for each requirement we simulate an ensemble of experiments with a $B_{s}^{0}$ lifetime of 1.63 ps, where the number of signal and background events as well as the background distributions are simulated according to data. For a broad range of selection requirements we observe the same uncertainty within a few percent. Our final requirement on the network output is chosen from the central region of this broad range of equivalent options.

iii.3 Physics backgrounds

We study possible physics backgrounds using simulated events with all $b$ -hadrons produced and decayed inclusively to final states containing a $J / ψ$ . For this study we use the selection from the branching fraction measurement. While several physics backgrounds appear in the $J / ψ π^{+} π^{-}$ mass spectrum, none contributes significantly under the $B_{s}^{0}$ peak. The most prominent physics backgrounds are $B^{0} \to J / ψ K^{* 0}$ with $K^{* 0} \to K^{+} π^{-}$ , where $K^{* 0}$ stands for $K^{*} (892)^{0}$ , and $B^{0} \to J / ψ π^{+} π^{-}$ . In the first case the kaon is mis-reconstructed as a pion and gives rise to a large fraction of the structure seen below 5.22 $G e V / c^{2}$ , while the second one is correctly reconstructed and produces the narrow peak at approximately 5.28 $G e V / c^{2}$ . Another possible physics type of background would consist of properly reconstructed $B^{+}$ combined with a random track. This type of background would contribute only to higher masses with a threshold above the $B_{s}^{0}$ signal. As we do not find evidence of such background in Ref. Aaltonen:2011sy () which is more sensitive we conclude that this kind of background is also negligible here. The stacked histogram of physics backgrounds derived from simulation is shown in Fig. 3. From this study we conclude that the main physics background that has to be included as a separate component in a fit to the mass spectrum above 5.26 $G e V / c^{2}$ stems from decays of $B^{0} \to J / ψ π^{+} π^{-}$ . It is properly reconstructed and therefore simple to parametrize. All other physics backgrounds are negligible.

Figure 3: (color online) Stacked histogram of physics backgrounds to $B_{s}^{0} \to J / ψ f_{0}$ derived from simulation using the selection for the branching fraction measurement. The vertical line indicates the location of the world average $B_{s}^{0}$ mass.

Iv Branching fraction measurement

In this Section we describe details of the branching fraction measurement. These involve the maximum likelihood fit to extract the number of signal events, the efficiency estimation, and the systematic uncertainties. We conclude this Section with the result for the ratio $R_{f_{0} / ϕ}$ of branching fractions between $B_{s}^{0} \to J / ψ f_{0}$ and $B_{s}^{0} \to J / ψ ϕ$ decays.

iv.1 Fit description

We use an unbinned extended maximum likelihood fit of the invariant mass to extract the number of $B_{s}^{0}$ decays in our samples. In order to avoid the need for modeling most of the physics background, we restrict the fit to the mass range from 5.26 $G e V / c^{2}$ to 5.5 $G e V / c^{2}$ . The likelihood is

$L = N \prod i = 1$	$[N_{s} \cdot P_{s} (m_{i}) + N_{c b} \cdot P_{c b} (m_{i}) +$	(9)
	$f_{p b} \cdot N_{s} \cdot P_{p b} (m_{i}) + N_{B^{0}} \cdot P_{B^{0}} (m_{i})] \cdot$
	$e^{- (N_{s} + N_{c b} + N_{s} \cdot f_{p b} + N_{B^{0}})},$

where $m_{i}$ is the invariant mass of the $i$ -th candidate and $N$ is the total number of candidates in the sample. The fit components are denoted by the subscripts $s$ for signal, $c b$ for combinatorial background, $p b$ for physics background, and $B^{0}$ for $B^{0} \to J / ψ π^{+} π^{-}$ background. The yields of the components are given by $N_{s}$ , $N_{c b}$ , $N_{s} \cdot f_{p b}$ , and $N_{B^{0}}$ , and their probability density functions (PDFs) by $P_{s, c b, p b, B^{0}} (m_{i})$ , respectively. The physics background yield is parametrized relative to the signal yield via the ratio $f_{p b}$ to allow constraining it by other measurements in the $B_{s}^{0} \to J / ψ ϕ$ fit.

The signal PDF $P_{s} (m_{i})$ is parametrized by a sum of two Gaussian functions with a common mean. The relative size of the two Gaussians and their widths are determined from simulated events. Approximately 82% of the $B_{s}^{0} \to J / ψ f_{0}$ decays are contained in a narrower Gaussian with width of 9.4 $M e V / c^{2}$ . The broader Gaussian has width of 18.4 $M e V / c^{2}$ . In the case of $B_{s}^{0} \to J / ψ ϕ$ , the narrow Gaussian with a width of 7.2 $M e V / c^{2}$ accounts for 79% of the signal, with the rest of the events having a width of 13.3 $M e V / c^{2}$ . To take into account possible differences between simulation and data, we multiply all widths by a scaling parameter $S_{m}$ . Because of kinematic differences between $f_{0} \to π^{+} π^{-}$ and $ϕ \to K^{+} K^{-}$ we use independent scale factors for both modes. In the fits all parameters of the PDF are fixed except for the scaling parameter $S_{m}$ . In addition the mean of the Gaussians is allowed to float in the $J / ψ K^{+} K^{-}$ fit. Doing so we obtain a value that is consistent with the world average $B_{s}^{0}$ mass Nakamura:2010zzi (). For the $J / ψ π^{+} π^{-}$ fit we fix the position of the signal to the value determined in the fit to the $J / ψ K^{+} K^{-}$ candidates.

The combinatorial background PDF $P_{c b} (m_{i})$ is parametrized using a linear function. In both fits we leave its slope floating. In each of the two fits there is one physics background. In the case of the $J / ψ π^{+} π^{-}$ spectrum, the physics background describes properly reconstructed $B^{0} \to J / ψ π^{+} π^{-}$ decays using a shape identical to the $B_{s}^{0}$ signal and position fixed to the world average $B^{0}$ mass Nakamura:2010zzi (). The number of $B^{0}$ events $N_{B^{0}}$ is left free in the fit. For the $J / ψ K^{+} K^{-}$ fit, we have a contribution from $B^{0} \to J / ψ K^{* 0}$ decays where the pion from the $K^{* 0}$ decay is mis-reconstructed as a kaon. This contribution peaks at a mass of approximately 5.36 $G e V / c^{2}$ with an asymmetric tail towards larger masses. The shape itself is parametrized by a sum of a Gaussian function and an exponential function convolved with a Gaussian. The parameters are derived from simulated $B^{0} \to J / ψ K^{* 0}$ events. The normalization of this component relative to the signal is fixed to $f_{p b} = (3.04 \pm 0.99) \times 10^{- 2}$ , which is derived from the CDF Run I measurement of the ratio of cross section times branching fraction for $B_{s}^{0} \to J / ψ ϕ$ and $B^{0} \to J / ψ K^{* 0}$ decays Abe:1996kc (), the world average branching fractions for $ϕ$ and $K^{* 0}$ Nakamura:2010zzi (), and the ratio of reconstruction efficiencies obtained from simulation.

The fit determines a yield of $502 \pm 37$ $B_{s}^{0} \to J / ψ f_{0}$ events and $2302 \pm 49$ $B_{s}^{0} \to J / ψ ϕ$ events, where the uncertainties are statistical only. The number of $B^{0}$ background events in the $J / ψ π^{+} π^{-}$ fit is $160 \pm 30$ .

iv.2 Efficiency

To extract the ratio of branching fractions we need to estimate the relative efficiency for reconstruction of $B_{s}^{0} \to J / ψ f_{0}$ with $f_{0} \to π^{+} π^{-}$ and $B_{s}^{0} \to J / ψ ϕ$ with $ϕ \to K^{+} K^{-}$ decays, $ϵ_{r e l} = ϵ (B_{s}^{0} \to J / ψ ϕ) / ϵ (B_{s}^{0} \to J / ψ f_{0})$ . We estimate the efficiency using simulated events in which we generate a single $B_{s}^{0}$ meson per event. The $B_{s}^{0}$ meson then decays with equal probabilities to $B_{s}^{0} \to J / ψ f_{0}$ or $B_{s}^{0} \to J / ψ ϕ$ final states with exclusive $J / ψ \to μ^{+} μ^{-}$ , $ϕ \to K^{+} K^{-}$ , and $f_{0} \to π^{+} π^{-}$ . Generated events are then processed through a detailed detector simulation and the offline reconstruction software used to reconstruct data. In both cases angular and decay time distributions are generated assuming no CP violation and parameters taken from the preliminary result of the angular distributions analysis beta_s (): $τ = 1.529 \pm 0.028 p s$ , $Δ Γ = 0.075 \pm 0.036 {p s}^{- 1}$ , $| A_{0} |^{2} = 0.524 \pm 0.020$ , and $| A_{| |} |^{2} = 0.231 \pm 0.021.$ As a strong phase between $A_{0}$ and $A_{| |}$ is not measured we use the world average value from $B^{0} \to J / ψ K^{* 0}$ decays of $ϕ_{| |} = - 2.86 \pm 0.11$ Nakamura:2010zzi () as a reasonable approximation Gronau:2008hb (). An additional peculiarity of the $B_{s}^{0} \to J / ψ f_{0}$ decay is the unusual mass shape of the $f_{0}$ meson. It is modeled using a Flatté distribution Flatte:1976xu () with input parameters measured by the BES experiment Ablikim:2004wn () to be $m_{0} = 965 \pm 8 \pm 6 M e V / c^{2}$ , $g_{π} = 165 \pm 10 \pm 15 M e V / c^{2}$ , and $g_{K} / g_{π} = 4.21 \pm 0.25 \pm 0.21$ , where the errors are statistical and systematic, respectively. The $ϕ$ meson mass distribution is modeled using a relativistic Breit-Wigner distribution with world average values for its parameters Nakamura:2010zzi (). With these inputs to the simulation we find $ϵ_{r e l} = 1.178$ , which accounts for the $ϕ$ and $f_{0}$ mass window selection requirements.

iv.3 Systematic uncertainties

We investigate several sources of systematic uncertainties. They can be broadly separated into two classes: one dealing with assumptions made in the fits that may affect yields, and the other related to assumptions in the efficiency estimation. In the first class we estimate uncertainties by refitting data with a modified assumption and taking the difference with respect to the original value as an uncertainty. For the second class we recalculate the efficiency with a modified assumption and take the difference with respect to the default efficiency as an uncertainty unless specified otherwise. The summary of assigned uncertainties is given in Table 1.

For the yield of $B_{s}^{0} \to J / ψ ϕ$ we investigate the effect of the assumption on the combinatorial background shape, the limited knowledge of mis-reconstructed $B^{0} \to J / ψ K^{* 0}$ decays and the shape of the signal PDF. The uncertainty due to the shape of combinatorial background is estimated by changing from the first order polynomial to a constant or a second order polynomial. For the physics background we vary the normalization of the component in the fit and use an alternative shape determined by varying the momentum distribution and the decay amplitudes of $B^{0} \to J / ψ K^{* 0}$ in simulation. Finally, to estimate the effect of the signal PDF parametrization we use an alternative model with a single Gaussian rather than two Gaussian functions and an alternative shape from simulation, where we vary the momentum distribution of the produced $B_{s}^{0}$ mesons and the decay amplitudes of the $B_{s}^{0} \to J / ψ ϕ$ decay.

To estimate the uncertainty on the $B_{s}^{0} \to J / ψ f_{0}$ yield we follow a procedure similar to that for $B_{s}^{0} \to J / ψ ϕ$ and conservatively treat the systematic effects as independent between the two modes in the calculation of $R_{f_{0} / ϕ}$ . For the sensitivity to the parametrization of the combinatorial background we switch to a second order polynomial or a constant as alternative parametrization. For the shape of the signal PDF we use two alternatives, one with a single Gaussian function instead of two and another one with two Gaussians, but varying the momentum distribution in simulation. We also vary the position of the $B_{s}^{0}$ signal within the uncertainty determined in the $J / ψ K^{+} K^{-}$ fit.

The systematic uncertainty on the relative efficiency stems from the statistics of simulation, an imperfect knowledge of the momentum distribution, physics parameters of decays like lifetimes or decay amplitudes, and differences in the efficiencies of the online selection of events. To estimate the effect of the imperfect knowledge of the momentum distribution we vary the momentum distribution of $B_{s}^{0}$ mesons in the simulation. The physics parameters entering the simulation are grouped into three categories, those defining the $f_{0}$ mass shape, the ones determining decay amplitudes in $B_{s}^{0} \to J / ψ ϕ$ decays, and those affecting the lifetimes of the two $B_{s}^{0}$ mass eigenstates. In the first two cases we vary each parameter independently and add all changes in the efficiency in quadrature. For the last case we vary the mean lifetime $τ$ and the decay width difference $Δ Γ$ simultaneously and take the largest variation as the uncertainty. We add the uncertainty from the third class in quadrature with all others to obtain the uncertainty due to the parameters describing the particle decays. The last effect deals with how events are selected during data taking. The CDF trigger has several different sets of requirements for the selection of events. The ones used in this analysis can be broadly sorted into three classes depending on momentum thresholds and which subdetectors detected muons. The fraction of events for each different class varies depending on the instantaneous luminosity, which is not simulated. To estimate the size of a possible effect we calculate the efficiency for each class separately and take half of the largest difference as the uncertainty.

To obtain the total uncertainty we add all partial uncertainties in quadrature. In total we assigned $49$ events (2.1%) as the systematic uncertainty on the $B_{s}^{0} \to J / ψ ϕ$ yield, $18$ events (3.6%) on the $B_{s}^{0} \to J / ψ f_{0}$ yield, and 0.040 (3.4%) on the relative efficiency $ϵ_{r e l}$ . A summary of the systematic uncertainties in the branching ratio is provided in Table 1.

Source	$J / ψ ϕ$ yield	$J / ψ f_{0}$ yield	$ϵ_{r e l}$
Combinatorial bckg.	34	16	$-$
Physics bckg.	13	$-$	$-$
Mass resolution	32	7.9	$-$
$B_{s}^{0}$ mass	$-$	0.1	$-$
Total	49	18	$-$
MC statistics	$-$	$-$

Measurement of branching ratio and B0s lifetime in the decay B0s→J/ψf0(980) at CDF

Abstract

pacs:

I Introduction

Ii CDF II detector and trigger

Iii Reconstruction and candidate selection

iii.1 Reconstruction

iii.2 Selection

iii.3 Physics backgrounds

Iv Branching fraction measurement

iv.1 Fit description

iv.2 Efficiency

iv.3 Systematic uncertainties

Measurement of branching ratio and $B_{s}^{0}$ lifetime in the decay $B_{s}^{0} \to J / ψ f_{0} (980)$ at CDF