Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in p\bar{p} Collisions at \sqrt{s}=1.96 TeV

Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in Collisions at  TeV

T. Aaltonen Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    J. Adelman Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    T. Akimoto University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M.G. Albrow Fermi National Accelerator Laboratory, Batavia, Illinois 60510    B. Álvarez González Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    S. Amerio University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    D. Amidei University of Michigan, Ann Arbor, Michigan 48109    A. Anastassov Rutgers University, Piscataway, New Jersey 08855    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    M. Aoki University of Illinois, Urbana, Illinois 61801    G. Apollinari Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Apresyan Purdue University, West Lafayette, Indiana 47907    T. Arisawa Waseda University, Tokyo 169, Japan    A. Artikov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    W. Ashmanskas Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Attal Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    A. Aurisano Texas A&M University, College Station, Texas 77843    F. Azfar University of Oxford, Oxford OX1 3RH, United Kingdom    P. Azzi-Bacchetta University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    P. Azzurri Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    N. Bacchetta University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    W. Badgett Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Barbaro-Galtieri Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    V.E. Barnes Purdue University, West Lafayette, Indiana 47907    B.A. Barnett The Johns Hopkins University, Baltimore, Maryland 21218    S. Baroiant University of California, Davis, Davis, California 95616    V. Bartsch University College London, London WC1E 6BT, United Kingdom    G. Bauer Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    P.-H. Beauchemin Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    F. Bedeschi Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Bednar Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia    S. Behari The Johns Hopkins University, Baltimore, Maryland 21218    G. Bellettini Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    J. Bellinger University of Wisconsin, Madison, Wisconsin 53706    A. Belloni Harvard University, Cambridge, Massachusetts 02138    D. Benjamin Duke University, Durham, North Carolina 27708    A. Beretvas Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Beringer Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    T. Berry University of Liverpool, Liverpool L69 7ZE, United Kingdom    A. Bhatti The Rockefeller University, New York, New York 10021    M. Binkley Fermi National Accelerator Laboratory, Batavia, Illinois 60510    D. Bisello University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    I. Bizjak University College London, London WC1E 6BT, United Kingdom    R.E. Blair Argonne National Laboratory, Argonne, Illinois 60439    C. Blocker Brandeis University, Waltham, Massachusetts 02254    B. Blumenfeld The Johns Hopkins University, Baltimore, Maryland 21218    A. Bocci Duke University, Durham, North Carolina 27708    A. Bodek University of Rochester, Rochester, New York 14627    V. Boisvert University of Rochester, Rochester, New York 14627    G. Bolla Purdue University, West Lafayette, Indiana 47907    A. Bolshov Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    D. Bortoletto Purdue University, West Lafayette, Indiana 47907    J. Boudreau University of Pittsburgh, Pittsburgh, Pennsylvania 15260    A. Boveia University of California, Santa Barbara, Santa Barbara, California 93106    B. Brau University of California, Santa Barbara, Santa Barbara, California 93106    A. Bridgeman University of Illinois, Urbana, Illinois 61801    L. Brigliadori Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    C. Bromberg Michigan State University, East Lansing, Michigan 48824    E. Brubaker Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    J. Budagov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    H.S. Budd University of Rochester, Rochester, New York 14627    S. Budd University of Illinois, Urbana, Illinois 61801    K. Burkett Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Busetto University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    P. Bussey Glasgow University, Glasgow G12 8QQ, United Kingdom    A. Buzatu Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    K. L. Byrum Argonne National Laboratory, Argonne, Illinois 60439    S. Cabrera Duke University, Durham, North Carolina 27708    M. Campanelli Michigan State University, East Lansing, Michigan 48824    M. Campbell University of Michigan, Ann Arbor, Michigan 48109    F. Canelli Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Canepa University of Pennsylvania, Philadelphia, Pennsylvania 19104    D. Carlsmith University of Wisconsin, Madison, Wisconsin 53706    R. Carosi Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    S. Carrillo University of Florida, Gainesville, Florida 32611    S. Carron Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    B. Casal Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    M. Casarsa Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Castro Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    P. Catastini Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    D. Cauz Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    M. Cavalli-Sforza Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    A. Cerri Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    L. Cerrito University College London, London WC1E 6BT, United Kingdom    S.H. Chang 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    Y.C. Chen Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    M. Chertok University of California, Davis, Davis, California 95616    G. Chiarelli Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    G. Chlachidze Fermi National Accelerator Laboratory, Batavia, Illinois 60510    F. Chlebana Fermi National Accelerator Laboratory, Batavia, Illinois 60510    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    D. Chokheli Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    J.P. Chou Harvard University, Cambridge, Massachusetts 02138    G. Choudalakis Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    S.H. Chuang Rutgers University, Piscataway, New Jersey 08855    K. Chung Carnegie Mellon University, Pittsburgh, PA 15213    W.H. Chung University of Wisconsin, Madison, Wisconsin 53706    Y.S. Chung University of Rochester, Rochester, New York 14627    C.I. Ciobanu University of Illinois, Urbana, Illinois 61801    M.A. Ciocci Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    A. Clark University of Geneva, CH-1211 Geneva 4, Switzerland    D. Clark Brandeis University, Waltham, Massachusetts 02254    G. Compostella University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    M.E. Convery Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Conway University of California, Davis, Davis, California 95616    B. Cooper University College London, London WC1E 6BT, United Kingdom    K. Copic University of Michigan, Ann Arbor, Michigan 48109    M. Cordelli Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy    G. Cortiana University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    F. Crescioli Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    C. Cuenca Almenar University of California, Davis, Davis, California 95616    J. Cuevas Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    R. Culbertson Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J.C. Cully University of Michigan, Ann Arbor, Michigan 48109    D. Dagenhart Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Datta Fermi National Accelerator Laboratory, Batavia, Illinois 60510    T. Davies Glasgow University, Glasgow G12 8QQ, United Kingdom    P. de Barbaro University of Rochester, Rochester, New York 14627    S. De Cecco Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    A. Deisher Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    G. De Lentdecker University of Rochester, Rochester, New York 14627    G. De Lorenzo Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    M. Dell’Orso Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    L. Demortier The Rockefeller University, New York, New York 10021    J. Deng Duke University, Durham, North Carolina 27708    M. Deninno Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    D. De Pedis Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    P.F. Derwent Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G.P. Di Giovanni LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France    C. Dionisi Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    B. Di Ruzza Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    J.R. Dittmann Baylor University, Waco, Texas 76798    M. D’Onofrio Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    S. Donati Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Dong University of California, Los Angeles, Los Angeles, California 90024    J. Donini University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    T. Dorigo University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    S. Dube Rutgers University, Piscataway, New Jersey 08855    J. Efron The Ohio State University, Columbus, Ohio 43210    R. Erbacher University of California, Davis, Davis, California 95616    D. Errede University of Illinois, Urbana, Illinois 61801    S. Errede University of Illinois, Urbana, Illinois 61801    R. Eusebi Fermi National Accelerator Laboratory, Batavia, Illinois 60510    H.C. Fang Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    S. Farrington University of Liverpool, Liverpool L69 7ZE, United Kingdom    W.T. Fedorko Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    R.G. Feild Yale University, New Haven, Connecticut 06520    M. Feindt Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    J.P. Fernandez Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain    C. Ferrazza Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    R. Field University of Florida, Gainesville, Florida 32611    G. Flanagan Purdue University, West Lafayette, Indiana 47907    R. Forrest University of California, Davis, Davis, California 95616    S. Forrester University of California, Davis, Davis, California 95616    M. Franklin Harvard University, Cambridge, Massachusetts 02138    J.C. Freeman Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    I. Furic University of Florida, Gainesville, Florida 32611    M. Gallinaro The Rockefeller University, New York, New York 10021    J. Galyardt Carnegie Mellon University, Pittsburgh, PA 15213    F. Garberson University of California, Santa Barbara, Santa Barbara, California 93106    J.E. Garcia Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    A.F. Garfinkel Purdue University, West Lafayette, Indiana 47907    K. Genser Fermi National Accelerator Laboratory, Batavia, Illinois 60510    H. Gerberich University of Illinois, Urbana, Illinois 61801    D. Gerdes University of Michigan, Ann Arbor, Michigan 48109    S. Giagu Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    V. Giakoumopolou Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Giannetti Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    K. Gibson University of Pittsburgh, Pittsburgh, Pennsylvania 15260    J.L. Gimmell University of Rochester, Rochester, New York 14627    C.M. Ginsburg Fermi National Accelerator Laboratory, Batavia, Illinois 60510    N. Giokaris Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    M. Giordani Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    P. Giromini Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy    M. Giunta Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    V. Glagolev Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    D. Glenzinski Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Gold University of New Mexico, Albuquerque, New Mexico 87131    N. Goldschmidt University of Florida, Gainesville, Florida 32611    A. Golossanov Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Gomez Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    G. Gomez-Ceballos Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    M. Goncharov Texas A&M University, College Station, Texas 77843    O. González Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain    I. Gorelov University of New Mexico, Albuquerque, New Mexico 87131    A.T. Goshaw Duke University, Durham, North Carolina 27708    K. Goulianos The Rockefeller University, New York, New York 10021    A. Gresele University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    S. Grinstein Harvard University, Cambridge, Massachusetts 02138    C. Grosso-Pilcher Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    R.C. Group Fermi National Accelerator Laboratory, Batavia, Illinois 60510    U. Grundler University of Illinois, Urbana, Illinois 61801    J. Guimaraes da Costa Harvard University, Cambridge, Massachusetts 02138    Z. Gunay-Unalan Michigan State University, East Lansing, Michigan 48824    C. Haber Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    K. Hahn Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    S.R. Hahn Fermi National Accelerator Laboratory, Batavia, Illinois 60510    E. Halkiadakis Rutgers University, Piscataway, New Jersey 08855    A. Hamilton University of Geneva, CH-1211 Geneva 4, Switzerland    B.-Y. Han University of Rochester, Rochester, New York 14627    J.Y. Han University of Rochester, Rochester, New York 14627    R. Handler University of Wisconsin, Madison, Wisconsin 53706    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    M. Hare Tufts University, Medford, Massachusetts 02155    S. Harper University of Oxford, Oxford OX1 3RH, United Kingdom    R.F. Harr Wayne State University, Detroit, Michigan 48201    R.M. Harris Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Hartz University of Pittsburgh, Pittsburgh, Pennsylvania 15260    K. Hatakeyama The Rockefeller University, New York, New York 10021    J. Hauser University of California, Los Angeles, Los Angeles, California 90024    C. Hays University of Oxford, Oxford OX1 3RH, United Kingdom    M. Heck Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    A. Heijboer University of Pennsylvania, Philadelphia, Pennsylvania 19104    B. Heinemann Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    J. Heinrich University of Pennsylvania, Philadelphia, Pennsylvania 19104    C. Henderson Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    M. Herndon University of Wisconsin, Madison, Wisconsin 53706    J. Heuser Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    S. Hewamanage Baylor University, Waco, Texas 76798    D. Hidas Duke University, Durham, North Carolina 27708    C.S. Hill University of California, Santa Barbara, Santa Barbara, California 93106    D. Hirschbuehl Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    A. Hocker Fermi National Accelerator Laboratory, Batavia, Illinois 60510    S. Hou Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    M. Houlden University of Liverpool, Liverpool L69 7ZE, United Kingdom    S.-C. Hsu University of California, San Diego, La Jolla, California 92093    B.T. Huffman University of Oxford, Oxford OX1 3RH, United Kingdom    R.E. Hughes The Ohio State University, Columbus, Ohio 43210    U. Husemann Yale University, New Haven, Connecticut 06520    J. Huston Michigan State University, East Lansing, Michigan 48824    J. Incandela University of California, Santa Barbara, Santa Barbara, California 93106    G. Introzzi Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    M. Iori Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    A. Ivanov University of California, Davis, Davis, California 95616    B. Iyutin Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    E. James Fermi National Accelerator Laboratory, Batavia, Illinois 60510    B. Jayatilaka Duke University, Durham, North Carolina 27708    D. Jeans Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    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    S. Jindariani University of Florida, Gainesville, Florida 32611    W. Johnson University of California, Davis, Davis, California 95616    M. Jones Purdue University, West Lafayette, Indiana 47907    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    S.Y. Jun Carnegie Mellon University, Pittsburgh, PA 15213    J.E. Jung 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    T.R. Junk University of Illinois, Urbana, Illinois 61801    T. Kamon Texas A&M University, College Station, Texas 77843    D. Kar University of Florida, Gainesville, Florida 32611    P.E. Karchin Wayne State University, Detroit, Michigan 48201    Y. Kato Osaka City University, Osaka 588, Japan    R. Kephart Fermi National Accelerator Laboratory, Batavia, Illinois 60510    U. Kerzel Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    V. Khotilovich Texas A&M University, College Station, Texas 77843    B. Kilminster The Ohio State University, Columbus, Ohio 43210    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    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    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    M.J. Kim Fermi National Accelerator Laboratory, Batavia, Illinois 60510    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    S.H. Kim University of Tsukuba, Tsukuba, Ibaraki 305, Japan    Y.K. Kim Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    N. Kimura University of Tsukuba, Tsukuba, Ibaraki 305, Japan    L. Kirsch Brandeis University, Waltham, Massachusetts 02254    S. Klimenko University of Florida, Gainesville, Florida 32611    M. Klute Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    B. Knuteson Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    B.R. Ko Duke University, Durham, North Carolina 27708    S.A. Koay University of California, Santa Barbara, Santa Barbara, California 93106    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    J. Konigsberg University of Florida, Gainesville, Florida 32611    A. Korytov University of Florida, Gainesville, Florida 32611    A.V. Kotwal Duke University, Durham, North Carolina 27708    J. Kraus University of Illinois, Urbana, Illinois 61801    M. Kreps Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    J. Kroll University of Pennsylvania, Philadelphia, Pennsylvania 19104    N. Krumnack Baylor University, Waco, Texas 76798    M. Kruse Duke University, Durham, North Carolina 27708    V. Krutelyov University of California, Santa Barbara, Santa Barbara, California 93106    T. Kubo University of Tsukuba, Tsukuba, Ibaraki 305, Japan    S. E. Kuhlmann Argonne National Laboratory, Argonne, Illinois 60439    T. Kuhr Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    N.P. Kulkarni Wayne State University, Detroit, Michigan 48201    Y. Kusakabe Waseda University, Tokyo 169, Japan    S. Kwang Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    A.T. Laasanen Purdue University, West Lafayette, Indiana 47907    S. Lai Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    S. Lami Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    S. Lammel Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Lancaster University College London, London WC1E 6BT, United Kingdom    R.L. Lander University of California, Davis, Davis, California 95616    K. Lannon The Ohio State University, Columbus, Ohio 43210    A. Lath Rutgers University, Piscataway, New Jersey 08855    G. Latino Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    I. Lazzizzera University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    T. LeCompte Argonne National Laboratory, Argonne, Illinois 60439    J. Lee University of Rochester, Rochester, New York 14627    J. 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    Y.J. 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    S.W. Lee Texas A&M University, College Station, Texas 77843    R. Lefèvre University of Geneva, CH-1211 Geneva 4, Switzerland    N. Leonardo Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    S. Leone Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    S. Levy Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    J.D. Lewis Fermi National Accelerator Laboratory, Batavia, Illinois 60510    C. Lin Yale University, New Haven, Connecticut 06520    C.S. Lin Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    J. Linacre University of Oxford, Oxford OX1 3RH, United Kingdom    M. Lindgren Fermi National Accelerator Laboratory, Batavia, Illinois 60510    E. Lipeles University of California, San Diego, La Jolla, California 92093    A. Lister University of California, Davis, Davis, California 95616    D.O. Litvintsev Fermi National Accelerator Laboratory, Batavia, Illinois 60510    T. Liu Fermi National Accelerator Laboratory, Batavia, Illinois 60510    N.S. Lockyer University of Pennsylvania, Philadelphia, Pennsylvania 19104    A. Loginov Yale University, New Haven, Connecticut 06520    M. Loreti University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    L. Lovas Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia    R.-S. Lu Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    D. Lucchesi University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    J. Lueck Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    C. Luci Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    P. Lujan Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    P. Lukens Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Lungu University of Florida, Gainesville, Florida 32611    L. Lyons University of Oxford, Oxford OX1 3RH, United Kingdom    J. Lys Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    R. Lysak Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia    E. Lytken Purdue University, West Lafayette, Indiana 47907    P. Mack Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    D. MacQueen Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    R. Madrak Fermi National Accelerator Laboratory, Batavia, Illinois 60510    K. Maeshima Fermi National Accelerator Laboratory, Batavia, Illinois 60510    K. Makhoul Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    T. Maki Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    P. Maksimovic The Johns Hopkins University, Baltimore, Maryland 21218    S. Malde University of Oxford, Oxford OX1 3RH, United Kingdom    S. Malik University College London, London WC1E 6BT, United Kingdom    G. Manca University of Liverpool, Liverpool L69 7ZE, United Kingdom    A. Manousakis Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    F. Margaroli Purdue University, West Lafayette, Indiana 47907    C. Marino Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    C.P. Marino University of Illinois, Urbana, Illinois 61801    A. Martin Yale University, New Haven, Connecticut 06520    M. Martin The Johns Hopkins University, Baltimore, Maryland 21218    V. Martin Glasgow University, Glasgow G12 8QQ, United Kingdom    M. Martínez Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    R. Martínez-Ballarín Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain    T. Maruyama University of Tsukuba, Tsukuba, Ibaraki 305, Japan    P. Mastrandrea Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    T. Masubuchi University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M.E. Mattson Wayne State University, Detroit, Michigan 48201    P. Mazzanti Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    K.S. McFarland University of Rochester, Rochester, New York 14627    P. McIntyre Texas A&M University, College Station, Texas 77843    R. McNulty 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    S. Menzemer Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    A. Menzione Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Merkel Purdue University, West Lafayette, Indiana 47907    C. Mesropian The Rockefeller University, New York, New York 10021    A. Messina Michigan State University, East Lansing, Michigan 48824    T. Miao Fermi National Accelerator Laboratory, Batavia, Illinois 60510    N. Miladinovic Brandeis University, Waltham, Massachusetts 02254    J. Miles Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    R. Miller Michigan State University, East Lansing, Michigan 48824    C. Mills Harvard University, Cambridge, Massachusetts 02138    M. Milnik Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    A. Mitra Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    G. Mitselmakher University of Florida, Gainesville, Florida 32611    H. Miyake University of Tsukuba, Tsukuba, Ibaraki 305, Japan    S. Moed Harvard University, Cambridge, Massachusetts 02138    N. Moggi Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    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    R. Moore Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Morello Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Movilla Fernandez Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    J. Mülmenstädt Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    A. Mukherjee Fermi National Accelerator Laboratory, Batavia, Illinois 60510    Th. Muller Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    R. Mumford The Johns Hopkins University, Baltimore, Maryland 21218    P. Murat Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Mussini Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    J. Nachtman Fermi National Accelerator Laboratory, Batavia, Illinois 60510    Y. Nagai University of Tsukuba, Tsukuba, Ibaraki 305, Japan    A. Nagano University of Tsukuba, Tsukuba, Ibaraki 305, Japan    J. Naganoma Waseda University, Tokyo 169, Japan    K. Nakamura University of Tsukuba, Tsukuba, Ibaraki 305, Japan    I. Nakano Okayama University, Okayama 700-8530, Japan    A. Napier Tufts University, Medford, Massachusetts 02155    V. Necula Duke University, Durham, North Carolina 27708    C. Neu University of Pennsylvania, Philadelphia, Pennsylvania 19104    M.S. Neubauer University of Illinois, Urbana, Illinois 61801    J. Nielsen Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    L. Nodulman Argonne National Laboratory, Argonne, Illinois 60439    M. Norman University of California, San Diego, La Jolla, California 92093    O. Norniella University of Illinois, Urbana, Illinois 61801    E. Nurse University College London, London WC1E 6BT, United Kingdom    S.H. Oh Duke University, Durham, North Carolina 27708    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    I. Oksuzian University of Florida, Gainesville, Florida 32611    T. Okusawa Osaka City University, Osaka 588, Japan    R. Oldeman University of Liverpool, Liverpool L69 7ZE, United Kingdom    R. Orava Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    K. Osterberg Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    S. Pagan Griso University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy    C. Pagliarone Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    E. Palencia Fermi National Accelerator Laboratory, Batavia, Illinois 60510    V. Papadimitriou Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Papaikonomou Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    A.A. Paramonov Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    B. Parks The Ohio State University, Columbus, Ohio 43210    S. Pashapour Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    J. Patrick Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Pauletta Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    M. Paulini Carnegie Mellon University, Pittsburgh, PA 15213    C. Paus Massachusetts Institute of Technology, Cambridge, Massachusetts 02139    D.E. Pellett University of California, Davis, Davis, California 95616    A. Penzo Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    T.J. Phillips Duke University, Durham, North Carolina 27708    G. Piacentino Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    J. Piedra LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France    L. Pinera University of Florida, Gainesville, Florida 32611    K. Pitts University of Illinois, Urbana, Illinois 61801    C. Plager University of California, Los Angeles, Los Angeles, California 90024    L. Pondrom University of Wisconsin, Madison, Wisconsin 53706    X. Portell Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    O. Poukhov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    N. Pounder University of Oxford, Oxford OX1 3RH, United Kingdom    F. Prakoshyn Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    A. Pronko Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Proudfoot Argonne National Laboratory, Argonne, Illinois 60439    F. Ptohos Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Punzi Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    J. Pursley University of Wisconsin, Madison, Wisconsin 53706    J. Rademacker University of Oxford, Oxford OX1 3RH, United Kingdom    A. Rahaman University of Pittsburgh, Pittsburgh, Pennsylvania 15260    V. Ramakrishnan University of Wisconsin, Madison, Wisconsin 53706    N. Ranjan Purdue University, West Lafayette, Indiana 47907    I. Redondo Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain    B. Reisert Fermi National Accelerator Laboratory, Batavia, Illinois 60510    V. Rekovic University of New Mexico, Albuquerque, New Mexico 87131    P. Renton University of Oxford, Oxford OX1 3RH, United Kingdom    M. Rescigno Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    S. Richter Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    F. Rimondi Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy    L. Ristori Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    A. Robson Glasgow University, Glasgow G12 8QQ, United Kingdom    T. Rodrigo Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    E. Rogers University of Illinois, Urbana, Illinois 61801    S. Rolli Tufts University, Medford, Massachusetts 02155    R. Roser Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M. Rossi Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    R. Rossin University of California, Santa Barbara, Santa Barbara, California 93106    P. Roy Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    A. Ruiz Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    J. Russ Carnegie Mellon University, Pittsburgh, PA 15213    V. Rusu Fermi National Accelerator Laboratory, Batavia, Illinois 60510    H. Saarikko Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    A. Safonov Texas A&M University, College Station, Texas 77843    W.K. Sakumoto University of Rochester, Rochester, New York 14627    G. Salamanna Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    O. Saltó Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain    L. Santi Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    S. Sarkar Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    L. Sartori Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    K. Sato Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Savoy-Navarro LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France    T. Scheidle Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    P. Schlabach Fermi National Accelerator Laboratory, Batavia, Illinois 60510    E.E. Schmidt Fermi National Accelerator Laboratory, Batavia, Illinois 60510    M.A. Schmidt Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    M.P. Schmidt Yale University, New Haven, Connecticut 06520    M. Schmitt Northwestern University, Evanston, Illinois 60208    T. Schwarz University of California, Davis, Davis, California 95616    L. Scodellaro Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain    A.L. Scott University of California, Santa Barbara, Santa Barbara, California 93106    A. Scribano Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    F. Scuri Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    A. Sedov Purdue University, West Lafayette, Indiana 47907    S. Seidel University of New Mexico, Albuquerque, New Mexico 87131    Y. Seiya Osaka City University, Osaka 588, Japan    A. Semenov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    L. Sexton-Kennedy Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A. Sfyrla University of Geneva, CH-1211 Geneva 4, Switzerland    S.Z. Shalhout Wayne State University, Detroit, Michigan 48201    M.D. Shapiro Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    T. Shears University of Liverpool, Liverpool L69 7ZE, United Kingdom    P.F. Shepard University of Pittsburgh, Pittsburgh, Pennsylvania 15260    D. Sherman Harvard University, Cambridge, Massachusetts 02138    M. Shimojima University of Tsukuba, Tsukuba, Ibaraki 305, Japan    M. Shochet Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    Y. Shon University of Wisconsin, Madison, Wisconsin 53706    I. Shreyber University of Geneva, CH-1211 Geneva 4, Switzerland    A. Sidoti Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    P. Sinervo Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    A. Sisakyan Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    A.J. Slaughter Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Slaunwhite The Ohio State University, Columbus, Ohio 43210    K. Sliwa Tufts University, Medford, Massachusetts 02155    J.R. Smith University of California, Davis, Davis, California 95616    F.D. Snider Fermi National Accelerator Laboratory, Batavia, Illinois 60510    R. Snihur Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    M. Soderberg University of Michigan, Ann Arbor, Michigan 48109    A. Soha University of California, Davis, Davis, California 95616    S. Somalwar Rutgers University, Piscataway, New Jersey 08855    V. Sorin Michigan State University, East Lansing, Michigan 48824    J. Spalding Fermi National Accelerator Laboratory, Batavia, Illinois 60510    F. Spinella Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    T. Spreitzer Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    P. Squillacioti Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    M. Stanitzki Yale University, New Haven, Connecticut 06520    R. St. Denis Glasgow University, Glasgow G12 8QQ, United Kingdom    B. Stelzer University of California, Los Angeles, Los Angeles, California 90024    O. Stelzer-Chilton University of Oxford, Oxford OX1 3RH, United Kingdom    D. Stentz Northwestern University, Evanston, Illinois 60208    J. Strologas University of New Mexico, Albuquerque, New Mexico 87131    D. Stuart University of California, Santa Barbara, Santa Barbara, California 93106    J.S. Suh 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    A. Sukhanov University of Florida, Gainesville, Florida 32611    H. Sun Tufts University, Medford, Massachusetts 02155    I. Suslov Joint Institute for Nuclear Research, RU-141980 Dubna, Russia    T. Suzuki University of Tsukuba, Tsukuba, Ibaraki 305, Japan    A. Taffard University of Illinois, Urbana, Illinois 61801    R. Takashima Okayama University, Okayama 700-8530, Japan    Y. Takeuchi University of Tsukuba, Tsukuba, Ibaraki 305, Japan    R. Tanaka Okayama University, Okayama 700-8530, Japan    M. Tecchio University of Michigan, Ann Arbor, Michigan 48109    P.K. Teng Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    K. Terashi The Rockefeller University, New York, New York 10021    J. Thom Fermi National Accelerator Laboratory, Batavia, Illinois 60510    A.S. Thompson Glasgow University, Glasgow G12 8QQ, United Kingdom    G.A. Thompson University of Illinois, Urbana, Illinois 61801    E. Thomson University of Pennsylvania, Philadelphia, Pennsylvania 19104    P. Tipton Yale University, New Haven, Connecticut 06520    V. Tiwari Carnegie Mellon University, Pittsburgh, PA 15213    S. Tkaczyk Fermi National Accelerator Laboratory, Batavia, Illinois 60510    D. Toback Texas A&M University, College Station, Texas 77843    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    T. Tomura University of Tsukuba, Tsukuba, Ibaraki 305, Japan    D. Tonelli Fermi National Accelerator Laboratory, Batavia, Illinois 60510    S. Torre Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy    D. Torretta Fermi National Accelerator Laboratory, Batavia, Illinois 60510    S. Tourneur LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France    W. Trischuk Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    Y. Tu University of Pennsylvania, Philadelphia, Pennsylvania 19104    N. Turini Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    F. Ukegawa University of Tsukuba, Tsukuba, Ibaraki 305, Japan    S. Uozumi University of Tsukuba, Tsukuba, Ibaraki 305, Japan    S. Vallecorsa University of Geneva, CH-1211 Geneva 4, Switzerland    N. van Remortel Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland    A. Varganov University of Michigan, Ann Arbor, Michigan 48109    E. Vataga University of New Mexico, Albuquerque, New Mexico 87131    F. Vázquez University of Florida, Gainesville, Florida 32611    G. Velev Fermi National Accelerator Laboratory, Batavia, Illinois 60510    C. Vellidis Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    V. Veszpremi Purdue University, West Lafayette, Indiana 47907    M. Vidal Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain    R. Vidal Fermi National Accelerator Laboratory, Batavia, Illinois 60510    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    T. Vine University College London, London WC1E 6BT, United Kingdom    M. Vogel University of New Mexico, Albuquerque, New Mexico 87131    I. Volobouev Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    G. Volpi Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy    F. Würthwein University of California, San Diego, La Jolla, California 92093    P. Wagner University of Pennsylvania, Philadelphia, Pennsylvania 19104    R.G. Wagner Argonne National Laboratory, Argonne, Illinois 60439    R.L. Wagner Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Wagner-Kuhr Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    W. Wagner Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany    T. Wakisaka Osaka City University, Osaka 588, Japan    R. Wallny University of California, Los Angeles, Los Angeles, California 90024    S.M. Wang Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China    A. Warburton Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    D. Waters University College London, London WC1E 6BT, United Kingdom    M. Weinberger Texas A&M University, College Station, Texas 77843    W.C. Wester III Fermi National Accelerator Laboratory, Batavia, Illinois 60510    B. Whitehouse Tufts University, Medford, Massachusetts 02155    D. Whiteson University of Pennsylvania, Philadelphia, Pennsylvania 19104    A.B. Wicklund Argonne National Laboratory, Argonne, Illinois 60439    E. Wicklund Fermi National Accelerator Laboratory, Batavia, Illinois 60510    G. Williams Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7    H.H. Williams University of Pennsylvania, Philadelphia, Pennsylvania 19104    P. Wilson Fermi National Accelerator Laboratory, Batavia, Illinois 60510    B.L. Winer The Ohio State University, Columbus, Ohio 43210    P. Wittich Fermi National Accelerator Laboratory, Batavia, Illinois 60510    S. Wolbers Fermi National Accelerator Laboratory, Batavia, Illinois 60510    C. Wolfe Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    T. Wright University of Michigan, Ann Arbor, Michigan 48109    X. Wu University of Geneva, CH-1211 Geneva 4, Switzerland    S.M. Wynne University of Liverpool, Liverpool L69 7ZE, United Kingdom    A. Yagil University of California, San Diego, La Jolla, California 92093    K. Yamamoto Osaka City University, Osaka 588, Japan    J. Yamaoka Rutgers University, Piscataway, New Jersey 08855    T. Yamashita Okayama University, Okayama 700-8530, Japan    C. Yang Yale University, New Haven, Connecticut 06520    U.K. Yang Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    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    W.M. Yao Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720    G.P. Yeh Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J. Yoh Fermi National Accelerator Laboratory, Batavia, Illinois 60510    K. Yorita Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637    T. Yoshida Osaka City University, Osaka 588, Japan    G.B. Yu University of Rochester, Rochester, New York 14627    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    S.S. Yu Fermi National Accelerator Laboratory, Batavia, Illinois 60510    J.C. Yun Fermi National Accelerator Laboratory, Batavia, Illinois 60510    L. Zanello Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy    A. Zanetti Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy    I. Zaw Harvard University, Cambridge, Massachusetts 02138    X. Zhang University of Illinois, Urbana, Illinois 61801    Y. Zheng University of California, Los Angeles, Los Angeles, California 90024    S. Zucchelli Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy
July 12, 2019
Abstract

This paper describes the first measurement of -quark fragmentation fractions into bottom hadrons in Run II of the Tevatron Collider at Fermilab. The result is based on a 360 pb sample of data collected with the CDF II detector in  collisions at  TeV. Semileptonic decays of , , and  mesons, as well as  baryons, are reconstructed. For an effective bottom hadron  threshold of 7 GeV, the fragmentation fractions are measured to be , , and , where the uncertainty is due to uncertainties on measured branching ratios. The value of agrees within one standard deviation with previous CDF measurements and the world average of this quantity, which is dominated by LEP measurements. However, the ratio is approximately twice the value previously measured at LEP. The approximately 2  discrepancy is examined in terms of kinematic differences between the two production environments.

pacs:
13.20.He, 13.30.Ce, 14.20.Mr, 14.40.Nd, 14.65.Fy

CDF Collaboration111With visitors from University of Athens, 15784 Athens, Greece, Chinese Academy of Sciences, Beijing 100864, China, University of Bristol, Bristol BS8 1TL, United Kingdom, University Libre de Bruxelles, B-1050 Brussels, Belgium, University of California Irvine, Irvine, CA 92697, University of California Santa Cruz, Santa Cruz, CA 95064, Cornell University, Ithaca, NY 14853, University of Cyprus, Nicosia CY-1678, Cyprus, University College Dublin, Dublin 4, Ireland, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom, University of Heidelberg, D-69120 Heidelberg, Germany, Universidad Iberoamericana, Mexico D.F., Mexico, University of Manchester, Manchester M13 9PL, England, Nagasaki Institute of Applied Science, Nagasaki, Japan, University de Oviedo, E-33007 Oviedo, Spain, Queen Mary, University of London, London, E1 4NS, England, Texas Tech University, Lubbock, TX 79409, IFIC(CSIC-Universitat de Valencia), 46071 Valencia, Spain,

I Introduction

Bottom quarks, , produced in collisions combine with anti-quarks or di-quarks to form bottom hadrons. In this process, called fragmentation, the color force field creates quark-antiquark pairs that combine with the bottom quark to create a  meson or baryon . Since the fragmentation process, which is governed by the strong force, cannot be reliably calculated by perturbative QCD Politzer (1973); Gross and Wilczek (1973); Field and Feynman (1978), the fragmentation properties of  quarks must be determined empirically. This paper describes a measurement of the species dependence of the -quark fragmentation rates into bottom hadrons produced in  collisions at center of mass energy  TeV during Run II of the Tevatron collider at Fermilab.

The probabilities that the fragmentation of a  quark will result in a  ,  , or   meson or a   baryon are denoted by , , , and , respectively. In this paper, indicates the fragmentation fraction integrated above the momentum threshold of sensitivity in the data:  Ref (). In the case that the fragmentation fractions are momentum dependent, the measured fragmentation fractions are proportional to the relative yields of the bottom hadrons integrated above the effective . The contributions from the production of excited bottom hadrons that decay into final states containing a , ,  meson or  baryon are implicitly included in this definition of the fragmentation fractions, . Throughout the paper, unless otherwise noted, references to a specific charge state are meant to imply the charge conjugate state as well.

In Run I of the Fermilab Tevatron, which collected data from 1992 - 1996, the fraction of  mesons produced relative to the number of  mesons was measured  2  higher at CDF Abe et al. (1996, 1999); Affolder et al. (2000a) than at the LEP experiments Abreu et al. (1992); Acton et al. (1992); Buskulic et al. (1995). Interestingly, the time-integrated flavor averaged mixing parameter, , where and are the time-integrated mixing parameters of and mesons respectively, was also measured  2  higher in Run I Abe et al. (1997); Acosta et al. (2004a) than the LEP averages of the same quantity Buskulic et al. (1992, 1994); Abreu et al. (1994); Acciarri et al. (2000); Abreu et al. (2001); Abbiendi et al. (2003). This second discrepancy led to speculations about possible sources of the enhanced average mixing rate at a hadron collider relative to electron-positron collisions, including suggestions that new physics may be the source of the disagreement Berger et al. (2001). Since the average momentum of  quarks produced at LEP,  40 GeV, is significantly higher than at the Tevatron,  10 GeV, it is also possible that the fragmentation process depends on the -quark momentum. Another possible explanation is that  is higher at the Tevatron than at LEP due to the different initial mechanism of -quark production. Of course, a more mundane possibility is that the Run I results relating to are simply statistical fluctuations. To shed light on the question of whether -quark fragmentation is different in a hadron environment than in  collisions, the fragmentation fractions are measured in CDF Run II with high statistical precision and an updated treatment of the lepton-charm sample composition.

The analysis strategy is as follows. Semileptonic decays of bottom hadrons, , where stands for electron or muon, and represents a charm meson or baryon, in case of semileptonic bottom baryon decays, unless otherwise specified, provide large samples for studying the fragmentation properties of  quarks. This measurement determines the -quark fragmentation fractions by reconstructing five semileptonic signatures, , , , , and . The selection requirements are kept similar among the five lepton-charm channels in order to cancel as many systematic uncertainties as possible. The final signal requirements, though similar, have been selected to maintain good acceptance for the individual decays, which have different kinematic features. The reconstructed  signal yields, originating from the various semileptonic decays, are then related to the numbers of bottom hadrons (, , , or ) produced in the -quark fragmentation process. Since the neutrino from the semileptonic bottom hadron decay is not reconstructed, the missing energy in the decay allows semileptonic bottom hadron decays to excited charm states to contribute to the five final state decay signatures. This results in “cross-talk” between the bottom hadron species, particularly between the  mesons. The observed semileptonic  decay signatures are related to their corresponding parent bottom hadrons through a procedure used to extract the sample composition, as described later in the text. In order to reduce systematic uncertainties in trigger and tracking efficiencies, the -quark fragmentation fractions are measured relative to . This means that the relative fragmentation fractions ,  and  are extracted from the five lepton-charm yields, taking the sample composition into account. Since the fragmentation of  quarks into  baryons other than the  are ignored, a constraint requiring the fragmentation fractions , , , and  to sum to unity is not applied.

This paper is organized as follows. The semileptonic signal reconstruction is discussed in Section II, while the sample composition procedure used to relate the lepton-charm signatures to the parent bottom hadron is described in Section III. The efficiencies needed to extract the sample composition are determined in Section IV. The fit to the fragmentation fractions is detailed in Section V. Finally, the systematic uncertainties assigned to the measurement are described in Section VI and the final results are discussed in Section VII.

Ii Data Reconstruction

ii.1 Experimental Apparatus

The data used in this measurement represent an integrated luminosity of approximately 360 pb collected with the CDF II detector between February 2002, and August 2004. The CDF detector employs a cylindrical geometry around the interaction region with the proton direction defining the positive -direction. Most of the quantities used for candidate selection are measured in the plane transverse to the -axis. In the CDF coordinate system, is the azimuthal angle, is the polar angle measured from the proton direction, and is the radius perpendicular to the beam axis. The pseudorapidity is defined as . The transverse momentum, , is the component of the track momentum, , transverse to the -axis (), while , with being the energy measured in the calorimeter.

The CDF II detector features excellent lepton identification and charged particle tracking and is described in detail elsewhere Acosta et al. (2005a); Blair et al. (1996). The parts of the detector relevant to the reconstruction of semileptonic bottom hadron decays used in this measurement are briefly summarized below. The detector nearest to the interaction region is a silicon vertex detector (SVX II) Sill (2000), which consists of five concentric layers of double-sided sensors located at radii between 2.5 and 10.6 cm. An additional single layer of silicon (L00) Hill (2004) is mounted on the beam pipe at radius  1.5 cm, but the information from this detector is not used in this measurement. In addition, two forward layers plus one central layer of double sided silicon located outside the SVX at radii of 20-29 cm make up the intermediate silicon layers (ISL) Affolder et al. (2000b). Together with the SVX II, the ISL detector extends the sensitive region of the CDF II tracking detector to . CDF’s silicon system provides three-dimensional track reconstruction and is used to identify displaced vertices associated with bottom hadron decays. The measurement of the momentum of charged particles in the silicon detector is significantly improved with the central outer tracker (COT) Affolder et al. (2004), an open-cell drift chamber with 30,200 sense wires arranged in 96 layers combined into four axial and four stereo super-layers (SL). It provides tracking from a radius of  40 cm out to a radius of 132 cm covering  cm. The track reconstruction efficiency of the COT is found to be for charged particles with  Acosta et al. (2004b) and  Acosta et al. (2003) for charged particles with . For high-momentum charged particles, the resolution is found to be . The COT also provides specific energy loss, dd, information for charged particle identification with a separation between pions and kaons of approximately 1.4  Abulencia et al. (2006a). The central tracking system is immersed in a superconducting solenoid that provides a 1.4 T axial magnetic field.

Electromagnetic (CEM) Balka et al. (1988) and hadronic (CHA) Bertolucci et al. (1988) calorimeters are located outside the COT and the solenoid, where they are arranged in a projective-tower geometry. The electromagnetic and hadronic calorimeters are lead-scintillator and iron-scintillator sampling devices, respectively. The energy resolution for the CDF central calorimeter is for electromagnetic showers Balka et al. (1988); Abulencia et al. (2007) and for hadrons Blair et al. (1996); Bertolucci et al. (1988), where is measured in GeV. A layer of proportional chambers (CES), with wire and strip readout, is located six radiation lengths deep in the CEM calorimeters, near the electromagnetic shower maximum. The CES provides a measurement of electromagnetic shower profiles in both the - and -directions for use in electron identification. Muon candidates are identified with two sets of multi-layer drift chambers and scintillator counters Ascoli et al. (1988); Dorigo (2001), one located outside the calorimeters (CMU) and the other (CMP) behind an additional 60 cm of iron shielding, equivalent to approximately 3 pion interaction lengths. The CMU provides coverage for particles with and . The CMP covers the same pseudorapidity region, but identifies muons with with higher purity than muons reconstructed in the CMU only.

ii.2 Trigger Requirements

CDF uses a three-level trigger system Blair et al. (1996), where each level provides a rate reduction sufficient to allow for processing at the next level with minimal dead-time. At level 1, data from every beam crossing are stored in a pipeline memory capable of buffering data for . The level 1 trigger either rejects an event or copies the data into one of four level 2 buffers. At level 2, a substantial fraction of the event data is available for analysis by the dedicated trigger processors. Events that pass the level 1 and level 2 trigger selection criteria are then sent to the level 3 trigger Anikeev et al. (2000, 2001), a cluster of computers running a speed-optimized reconstruction code. Events selected by level 3 are written to permanent mass storage.

Tracking plays a significant role in the triggers utilized for this analysis. Semileptonic  decays are recorded using a trigger that requires a lepton and a track displaced from the interaction point and identified with the silicon vertex trigger (SVT) Bardi et al. (2002). The decay topology of semileptonic  decays is sketched in Fig. 1. Tracks are reconstructed at level 1 with the extremely fast tracker (XFT) Thomson et al. (2002) by examining COT hits from the four axial super-layers. The XFT provides - tracking information and can identify tracks with  GeV with high efficiency () and good transverse momentum resolution, . XFT tracks can be matched with either calorimeter clusters to identify electron candidates or with track segments in the muon detectors to identify muon candidates. The XFT tracks are extrapolated into the silicon detector system, where the SVT uses the SVX II measurements of charge deposits from charged particles to form simplified tracks. In addition, the SVT determines the distance of closest approach in the transverse plane, , with respect to the beam line, which is determined from a time-dependent line fit to the locus of primary interaction vertices determined from all tracks available at trigger level (see Fig. 1). The impact parameter resolution of the SVT is approximately Bardi et al. (2002); Ashmanskas et al. (2002), which includes a contribution of m from the width of the interaction region Acosta et al. (2005b).

The primary trigger used in this measurement requires that the lepton and the displaced track (SVT track) must have transverse momentum values greater than 4 GeV and 2 GeV, respectively. The displaced track’s impact parameter, , must exceed 120 m and be less than 1 mm to reject decay products of long-lived hadrons decays such as or . The opening angle, , between the lepton and SVT track is required to satisfy to increase the probability that the two tracks originate from the same hadron. Additionally, the invariant mass between the trigger lepton and SVT triggered track must be less than the nominal bottom hadron mass, , where the SVT track is assumed to have the pion mass. The trigger lepton requirements are described in conjunction with their analysis selections in Section II.3.1. Events that pass these trigger requirements are recorded to the lepton plus SVT trigger data stream for further analysis. In this measurement both the muon and electron plus SVT trigger data (+SVT and +SVT) are used. An additional trigger utilized for selecting  events is the two-track trigger (TTT), which requires two displaced tracks. Large semileptonic  samples are also available with this trigger Abulencia et al. (2006b, c), although the false lepton background is much larger as well. Semileptonic events from the TTT are used in this analysis for a study of the systematic uncertainty arising from false leptons.

Figure 1: Sketch of semileptonic -decay topology in the transverse plane, where is the primary vertex, is the decay vertex of the bottom hadron, is the decay vertex of the charm hadron, and is defined in the text. “SVT” indicates the track selected by the displaced track SVT trigger, which is also defined in the text.

ii.3 Data Selection and Reconstruction

Events from the lepton plus SVT trigger data stream are used to reconstruct semileptonic bottom hadron decays in this analysis. First, trigger leptons are identified by re-confirming the trigger decision with offline quantities after event reconstruction. Charm candidates are then reconstructed, with the SVT track required to match one of the daughter tracks from the charm decay. The selections on the lepton-charm signals obtained are optimized to reduce combinatoric background and improve signal significance. Non-combinatoric backgrounds in the charm signals are handled separately.

ii.3.1 Trigger Lepton Identification

The data analysis begins by identifying the trigger leptons from the +SVT and +SVT trigger streams. The electron candidates are identified by requiring the following selection criteria. The longitudinal shower profile must be consistent with that of an electron shower, with a leakage energy from the CEM into the CHA of less than 12.5%, in order to suppress hadron contamination. The lateral shower profile of the CEM cluster is required to be consistent with a profile obtained from test beam electrons after appropriate corrections. The association of a single track with the calorimeter shower is made based on the position matching at the CES plane, with both  cm and  cm conditions required. To achieve good agreement between data and Monte Carlo (MC) simulation (see Sec. IV.1), an isolation requirement is applied to the trigger electron candidates by requiring that exactly only one track is found that projects to the CEM towers used to define the electron energy. To reconfirm electron trigger cuts, the offline reconstructed and of the electron candidate are required to be greater than 4 GeV and 4 GeV, respectively. Additionally, electron candidates from photon conversions in the detector material are removed by rejecting those electron candidates that have a small opening angle with oppositely charged particles in the event.

Trigger muon candidates are reconstructed by extrapolating tracks measured in the COT to the muon system, where they are matched to track segments (stubs) reconstructed in the muon chambers. A CMU or CMP stub is required to have hits in at least three out of the four layers of planar drift chambers. Trigger muons are required to have hits in both the CMU and CMP muon chambers. The separation between a track segment reconstructed in the muon chamber and the extrapolated COT track is computed. The uncertainty in this quantity is dominated by multiple scattering in the traversed detector material. For good track to stub matching, this separation is required to be less than 15 cm and 20 cm in the -view for CMU and CMP, respectively. The transverse momentum of a muon candidate reconstructed offline is required to be greater than 4 GeV.

ii.3.2 Charm Candidate Selection

The SVT track is required to match one of the final state tracks in the five reconstructed charm signals: , , , , and . Only well-reconstructed tracks with and at least three silicon - hits are retained for offline analysis. To ensure good track quality, all charm daughter tracks, except for the soft pion from the  decay, are required to have at least five hits in at least two axial and two stereo COT super-layers. There are no COT requirements on the  soft pion. During data reconstruction the track parameters are corrected for the ionization energy loss appropriate to the mass hypothesis under consideration. In addition, tracks are required to be fiducial in the COT, so that only tracks which are well-described by the simulation (see Sec. IV.1) are used for further analysis. In particular, tracks that fall within  1.5 cm of the COT mid-plane, where no track information is recorded, and tracks that originate outside of the COT volume at  155 cm are excluded from the analysis. In addition, all tracks must at least pass through the axial SL 6 before exiting the COT. This means the exit radius of the track must be greater than the radius of the sixth super-layer = 106 cm. This requirement is tightened for the SVT trigger track and the trigger lepton. Both tracks must pass through SL 8 of the COT ( = 131 cm) as required in the trigger. The invariant mass of the  and is reconstructed within  GeVand  GeV, respectively. The reconstructed mass is required to be within  GeV, while the is reconstructed within  GeV. Finally, the reconstructed charm signals are combined with the triggered lepton in a three-dimensional kinematic fit constraining all tracks to a common vertex (see Fig. 1) to establish signals that can be related to semileptonic , , , and  decays. The vertex reconstruction does not use a constraint to the known  mass Eidelman et al. (2004), although  [GeV] is required in order to select a pure sample of candidates.

ii.3.3 Backgrounds to Lepton-Charm Signals

Several backgrounds affect the semileptonic  signals. Some of these can be reduced by judicious signal selection, while some must be included in the modeling of the signal or treated as sources of systematic uncertainties. The simplest of these backgrounds to understand are those events arising from combinatoric sources, which are generally estimated from the sidebands of the charm signal. In these backgrounds, random tracks are combined to form a charm signal which passes all charm selection requirements. This combinatoric background can most easily be reduced by selection requirements and modeled by the sideband events, which are expected to exhibit the same shape underneath the signal. A related, but more subtle type of background is that arising from the mis-identification of tracks in one charm decay arising from incorrect assignment of particle identifications in a real charm decay, resulting in ”reflection” backgrounds. These backgrounds are often flat beneath the signal of interest, but occasionally they exhibit particular shapes that can affect the signal distribution non-uniformly. Some reflection backgrounds can be effectively reduced with particle identification selections, such as the specific ionization of particles, dd (see Section II.3.4.) Other reflection backgrounds, which have non-uniform distribution in mass beneath the charm signal are included in the fit to the signal (see Section II.3.5.) MC simulated data is used to determine the shape of these reflection backgrounds.

The third type of background to the semileptonic signals arises from physical processes that produce a real lepton and charm hadron, but not through a decay directly to . This includes processes which originate from the same , such as , where , and , where . These “physics backgrounds” are included in the fit to the sample composition (see Section III). Other backgrounds include processes in which the lepton and charm hadron originate from separate and quark pairs, i.e. , , or , . The background gives a wrong sign (WS) lepton-charm combination, in which the charm and lepton have the same charge, while the background gives right sign (RS) lepton-charm combinations, in which the charm and lepton have opposite charge. All of these processes are also possible with a real charm hadron and a false lepton. In the case of false leptons, both right sign and wrong sign lepton-charm are expected to be present. Backgrounds which do not originate from the same  hadron are treated as a source of systematic uncertainty and described by the wrong sign lepton-charm events, which primarily describe false leptons (see Section VI.1.) The background is assumed to be small for a charm decaying to a lepton with  Gibson (2006) and is ignored, while the background is implicitly included in the false lepton systematic uncertainty.

ii.3.4 Signal Optimization

Requirements to further enhance the lepton-charm signal include cuts on the , , and charm daughter tracks, and cuts on the invariant mass of the lepton-charm system, , to limit feed-down from excited charm and lepton-charm combinations which do not originate from direct semileptonic bottom hadron decays. Requirements are also made on the probability of the charm and lepton-charm vertex fits.

Since bottom hadrons are longer-lived, a powerful discriminant against these backgrounds is a cut on the proper time of  candidate. The decay distance of the  hadron is determined by defining a quantity, , which is the transverse decay distance of the lepton-charm combination from the primary interaction vertex (PV), projected on the  momentum direction. The missing neutrino produced in the semileptonic decay prevents precise knowledge of and thus of the proper decay time of the  candidate. Instead, a pseudo proper decay time is constructed as:

(1)

A cut is applied to guarantee a signal from long-lived bottom hadrons and to reduce signal contamination from false leptons and other processes that can contribute a lepton and a charm hadron from uncorrelated sources (see also Section II.3.3.) This requirement also drastically reduces the combinatoric background of charm candidates with real leptons. A cut on the significance of the transverse decay distance of the charm meson, , also reduces the light flavored hadron contamination in the signal. A cut on is applied to improve agreement between the  data and Monte Carlo simulation used in determining the efficiencies (see Sec. IV). The selected  candidates are a subset of the  candidates. Instead of performing a vertex fit on the soft pion, , from the  decay, A tight cut is used to select a very clean  sample. This reduces the systematic uncertainty in the selection of the  combination relative to a  pair, since no additional vertex fit is performed. Consequently, the efficiency to detect the soft pion is better described by the simulation. Since the data agrees well with the simulation for tracks with greater than 400 MeV, as can be seen in Fig. 2, the soft pion efficiency is determined from the simulation. A tight cut is used to select a very clean  sample.

(a)(b)

Figure 2: Comparisons between data and simulation of , the soft pion from the  decay, for the (a) and (b) mode.

In order to determine the final analysis selection, kinematic selection criteria are optimized with respect to the combinatoric background for each lepton-charm channel, with additional cuts designed to limit non-combinatoric background, such as the and cuts, applied during the optimization. The figure of merit (FOM) used for optimization is . The signal, , is taken from inclusive and  Monte Carlo (see Sec. IV.1). The background, , is taken from the sidebands of the charm signal. In order for the FOM to accurately reflect the significance of the signals in data, is scaled to the expected data signal with a set of nominal cuts obtained by first optimizing each cut individually without applying any other cut. The cuts are then optimized a second time applying all optimal cuts from the prior optimization except the cut being optimized. After two or three successive iterations, a stable optimal cut point is reached for all cuts.

A particle identification cut using dd is found useful for reducing the combinatoric background in the  signal. The combinatoric background can be significantly reduced by correctly identifying the proton from the  decay utilizing the specific energy loss of the proton track measured in the COT. A dd likelihood ratio, , requirement is applied to the proton. The likelihood ratio is defined by the relation , where and . Figure 3 shows the resulting distributions for protons from the decay and kaons and pions from the decay with the proton hypothesis applied. Muons are indistinguishable from pions, while electrons are well-separated from all of the other distributions, since their mass is so much lower than the mass of the other particles. A cut on , as determined from the control samples, is applied to reduce background while keeping the proton efficiency high. This cut primarily removes pions, since the dd separation between protons and kaons is not as good.

N/0.01

Figure 3: dd  distribution for protons from and kaons and pions from with the proton hypothesis applied. Tracks with to the right of the dashed vertical line are identified as protons.

To cancel as many differences in signal reconstruction as possible, the selection criteria are kept as similar as is feasible across charm channels. The optimized cuts designed to limit both the combinatoric and some non-combinatoric backgrounds are unified to minimize the differences in selections between channels. However, some cuts, in which different optimal values are expected due to differences in the decay kinematics, are not forced to be similar. For example, the proper decay time of the  meson and  baryon differ by a factor of about five. The selection criteria applied to the lepton-charm decay signatures are listed in Table 1. Additional selection requirements to reduce non-combinatoric backgrounds are discussed next.

Selection cuts
 [cm] [-0.01,0.10] [-0.01,0.10] [-0.01,0.20] [-0.01,0.10] [-0.01,0.05]
 [cm] 0.02 0.02 0.02 0.02 0.02
 [cm] 0.04 0.04 0.04 0.04 0.04
 [GeV] [2.4,5.1] [2.4,5.1] [2.4,5.1] [2.4,5.1] [3.4,5.5]
[GeV] 5.0 5.0 N/A N/A N/A
[GeV] N/A N/A N/A N/A 2.0
[GeV] 0.6 0.6 0.6 0.6 0.6
10 10 10 10 5
vertex prob.
4.5 4.5 11 5 4.5
 [GeV] N/A [0.1440,0.1475] N/A N/A N/A
[GeV] N/A 0.4 N/A N/A N/A
 [GeV] N/A N/A N/A 0.0095 N/A
dd  N/A N/A N/A N/A 0.3
Table 1: Signal selection requirements.

ii.3.5 Reflection Backgrounds

The selection criteria discussed above (see Sec. II.3.4) optimize the signal sensitivity with respect to the combinatoric background. However, there are other non-combinatoric backgrounds that must be considered. This is partially achieved with the and cuts discussed previously. Another significant background arises from reflections, which occur when the particle identifications in charm decay are mis-assigned. For example, if the from a  decay is assigned the pion mass, the combination can contribute to the  signal. Figure 4 shows the shapes determined from MC for reflections from (a) , (b) , (c) , (d) , and (e)  decays when these decay channels are reconstructed as a different charm mode. The shapes are normalized to their expected contributions, e.g. assuming , where these numerical values are for illustrative purposes only. The  decay is the most significant reflection background below the  signal, shown in Fig. 4(c). This reflection is particularly problematic because the  reflection begins just underneath the real  signal. Potential - mis-identification is a significant consideration in the  signal, shown in Fig. 4(e). The  decay significantly contributes to the background beneath the  signal, although its contribution is flat underneath the signal.

(a)(b)

(c)(d)

(e)

Figure 4: Monte Carlo simulation reflection shapes for (a) , (b) , (c) , (d) , and (e) . The shapes are normalized to their expected contributions, assuming , used for illustrative purposes only.

The shape of the  reflection background beneath the  signal is determined from a Monte Carlo simulation (see Section IV.1) study, in which semileptonic  decays are generated. In these MC events  candidates are then reconstructed. The resulting invariant mass distribution is shown in Fig. 5. The normalization of the  reflection shape in the fit to the  signal is determined by reconstructing a  signal from the wide signal window, , shown in Fig. 6. A mass cut of , designed to reduce background to the  signal, is applied to the  decay. Monte Carlo simulation is then used to measure the efficiency of the  decay relative to the inclusive set of  decays that contribute to the reflection. The converse  reflection in the  signal is negligible due to the mass cut applied to the invariant mass.

Figure 5: Combined and  reflection into the invariant mass. The reflection is determined from an inclusive MC sample of , where all  meson decay modes are included.

(a)(b)

Figure 6: reconstructed in in the (a) +SVT and (b) +SVT data.

In a manner completely analogous to the way the  signal yield, , is determined in data, the  candidates decaying to the and states, and , respectively, are determined from the Monte Carlo simulation. The number of  mesons expected to contribute to the  signal can then be calculated by evaluating

(2)

where

(3)

The numbers of  candidates that contribute to the  lepton-charm samples in the wide mass window around the  signal are and . The normalization of the  reflection in the  signal is later constrained to the predicted number of  reflection events in the fit to the  signal (see Sec. II.4).

Since the  and  reflections in the  signal are relatively flat under the signal region, sideband subtraction is expected to remove the effect of the  and  reflections on the  signal distributions within statistical uncertainty. Correspondingly, the event count obtained by fitting the  signal is not expected to be significantly influenced by the presence of these backgrounds. Additionally, the dd cut applied to the proton (discussed in the previous section) reduces contamination from pions, which contribute to the  and reflections.

(a)(b)

(c)(d)

(e)(f)

Figure 7: +SVT right sign (RS) (points with error bars) and wrong sign (WS) (histogram) invariant mass distribution of (a) , (b) , (c) , (d) , (e)  with all cuts applied and (f) without the dd cut applied. The fit parameterizations described in the text are overlaid.

(a)(b)

(c)(d)

(e)(f)

Figure 8: +SVT right sign (RS) (points with error bars) and wrong sign (WS) (histogram) invariant mass distribution of (a) , (b) , (c) , (d) , (e)  with all cuts applied and (f) without the dd cut applied. The fit parameterizations described in the text are overlaid.

ii.4 Signal Yields

The , , , and mass spectra are fit to determine the number of lepton-charm events for the , , , , and samples. The invariant mass distributions of the charm signals are shown in Fig. 7 for the +SVT data and in Fig. 8 for the +SVT data with all lepton, charm, and lepton-charm selection criteria applied. The distributions are fit with a double Gaussian and linear background shape. The reflection of  decays into the  final state is included in the fit to the  signal. The normalization of the  reflection is constrained to the predicted number of  reflection events as described above. In order to keep the broad Gaussian and reflection shapes reasonably independent, the double Gaussian means and widths for the  are determined before the reflection shape is added to the fit. When the combined fit is performed, the parameters of the double Gaussian are constrained within their uncertainties. The fits to the , , , , and  charm signals for right sign lepton-charm pairs are shown in Fig. 7 for the +SVT data and in Fig. 8 for the +SVT data. The invariant mass distributions for wrong sign combinations of lepton-charm pairs, e.g. , are also included in Figs. 7 and 8, indicating no significant contributions of possible backgrounds, such as false leptons, to be present in the right sign signals (see also Sec. VI.1). The fitted lepton-charm yields are listed in Table 2. The  reflection is not included in the  yield, since the fit shape to the  includes a separate shape for the  reflection, as discussed in Section II.3.5. The dd cut flattens the background and reduces its overall level by a factor of five, while it reduces the signal by  35% in the +SVT data and  28% in the +SVT data as can be seen in Fig. 7(e)-(f) and Fig. 8(e)-(f).

+SVT +SVT
Decay Yield FOM Fit Prob. [%] Yield FOM Fit Prob. [%]
122 64.4 159 12.5
54.1 1.27 73.3 1.14
90.2 9.43 114 50.7
27.3 7.84 36.6 30.2
32.8 33.9 40.9 40.9
Table 2: Fitted signal yields for lepton-charm final states in 360 pb.

Iii Sample Composition Determination Procedure

This measurement uses flavor SU(3) symmetry to describe the branching fractions of semileptonic  meson decays; therefore, the partial widths of the semileptonic decays of  mesons are chosen to be equal, namely

(4)

where

(5)

This assumption is referred to as the spectator model, which also implies that the partial widths of the semileptonic bottom hadron decays into the pseudoscalar, vector, or higher excited  states are expected to be equal,