Eur. Phys. J. C (2006) 47: 547-587
https://doi.org/10.1140/epjc/s2006-02569-7

Experimental Physics

Search for neutral MSSM Higgs bosons at LEP

¹ Physikalisches Institut, RWTH-Aachen, 52056, Aachen, Germany
² Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, 74019, Annecy-le-Vieux Cedex, France
³ Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona, 08193, Bellaterra (Barcelona), Spain
⁴ Dipartimento di Fisica, INFN Sezione di Bari, 70126, Bari, Italy
⁵ Institute of High Energy Physics, Academia Sinica, Beijing, P.R. China
⁶ European Laboratory for Particle Physics (CERN), 1211, Geneva 23, Switzerland
⁷ Laboratoire de Physique Corpusculaire, Université Blaise Pascal, IN2P3-CNRS, Clermont-Ferrand, 63177, Aubière, France
⁸ Niels Bohr Institute, 2100, Copenhagen, Denmark
⁹ Nuclear Research Center Demokritos (NRCD), 15310, Attiki, Greece
¹⁰ Laoratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, 91128, Palaiseau Cedex, France
¹¹ Dipartimento di Fisica, Università di Firenze, INFN Sezione di Firenze, 50125, Firenze, Italy
¹² Laboratori Nazionali dell’INFN (LNF-INFN), 00044, Frascati, Italy
¹³ Department of Physics and Astronomy, University of Glasgow, Glasgow, G128QQ, UK
¹⁴ Utah Valley State College, Orem, UT, 84058, U.S.A.
¹⁵ Kirchhoff-Institut für Physik, Universität Heidelberg, 69120, Heidelberg, Germany
¹⁶ Department of Physics, Imperial College, London, SW7 2BZ, UK
¹⁷ Institut für Experimentalphysik, Universität Innsbruck, 6020, Innsbruck, Austria
¹⁸ Department of Physics, University of Lancaster, Lancaster, LA1 4YB, UK
¹⁹ Institut de Physique Nucléaire, Département de Physique, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
²⁰ Institut für Physik, Universität Mainz, 55099, Mainz, Germany
²¹ Centre de Physique des Particules de Marseille, Univ Méditerranée, IN2P3-CNRS, 13288, Marseille, France
²² Dipartimento di Fisica, Università di Milano e INFN Sezione di Milano, 20133, Milano, Italy
²³ Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805, München, Germany
²⁴ Laboratoire de l’Accélérateur Linéaire, Université de Paris-Sud, IN2P3-CNRS, 91898, Orsay Cedex, France
²⁵ Dipartimento di Fisica, Università, INFN Sezione di Pisa, e Scuola Normale Superiore, 56010, Pisa, Italy
²⁶ Department of Physics, Royal Holloway & Bedford New College, University of London, Egham, Surrey, TW20 OEX, UK
²⁷ Particle Physics Dept., Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 OQX, UK
²⁸ CEA, DAPNIA/Service de Physique des Particules, CE-Saclay, 91191, Gif-sur-Yvette Cedex, France
²⁹ Institute for Particle Physics, University of California at Santa Cruz, Santa Cruz, CA, 95064, USA
³⁰ Department of Physics, University of Sheffield, Sheffield, S3 7RH, UK
³¹ Fachbereich Physik, Universität Siegen, 57068, Siegen, Germany
³² Dipartimento di Fisica, Università di Trieste e INFN Sezione di Trieste, 34127, Trieste, Italy
³³ Experimental Elementary Particle Physics, University of Washington, Seattle, WA, 98195, U.S.A.
³⁴ Department of Physics, University of Wisconsin, Madison, WI, 53706, USA
³⁵ Institute for Particle Physics, ETH Hönggerberg, 8093, Zürich, Switzerland
³⁶ CERN, 1211, Geneva 23, Switzerland
³⁷ Fermilab, PO Box 500, MS 352, Batavia, IL, 60510, USA
³⁸ Dipartimento di Fisica di Catania and INFN Sezione di Catania, 95129, Catania, Italy
³⁹ Department of Physics, University of Florida, Gainesville, Florida, 32611-8440, USA
⁴⁰ INAF, IFSI sezione di Torino, Torino, Italy
⁴¹ Groupe d’Astroparticules de Montpellier, Université de Montpellier II, 34095, Montpellier, France
⁴² Departement de Physique Corpusculaire, Université de Genève, 1211, Genève 4, Switzerland
⁴³ Department of Physics, Tsinghua University, Beijing, P.R. China
⁴⁴ Universitat de Barcelona, 08208, Barcelona, Spain
⁴⁵ SAP AG, 69185, Walldorf, Germany
⁴⁶ Groupe d’ Astroparticules de Montpellier, Université de Montpellier II, 34095, Montpellier, France
⁴⁷ BNP Paribas, 60325, Frankfurt am Main, Germany
⁴⁸ Institut Inter-universitaire des hautes Energies (IIHE), CP 230, Université Libre de Bruxelles, 1050, Bruxelles, Belgium
⁴⁹ Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, Palermo, Italy
⁵⁰ SLAC, Stanford, CA, 94309, USA
⁵¹ CERN, 1211, Geneva 23, Switzerland
⁵² Liverpool University, Liverpool, L69 7ZE, UK
⁵³ Henryk Niewodnicznski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
⁵⁴ Department of Physics and Astronomy, Iowa State University, Ames, IA, 50011-3160, USA
⁵⁵ Physics Department, Universiteit Antwerpen, Universiteitsplein 1, 2610, Antwerpen, Belgium
⁵⁶ IIHE, ULB-VUB, Pleinlaan 2, 1050, Brussels, Belgium
⁵⁷ Faculté des Sciences, Univ. de l’Etat Mons, Av. Maistriau 19, 7000, Mons, Belgium
⁵⁸ Physics Laboratory, University of Athens, Solonos Str. 104, 10680, Athens, Greece
⁵⁹ Department of Physics, University of Bergen, Allégaten 55, 5007, Bergen, Norway
⁶⁰ Dipartimento di Fisica, Università di Bologna and INFN, Via Irnerio 46, 40126, Bologna, Italy
⁶¹ Centro Brasileiro de Pesquisas Físicas, rua Xavier Sigaud 150, 22290, Rio de Janeiro, Brazil
⁶² Depto. de Física, Pont. Univ. Católica, C.P. 38071, 22453, Rio de Janeiro, Brazil
⁶³ Inst. de Física, Univ. Estadual do Rio de Janeiro, rua São Francisco Xavier 524, Rio de Janeiro, Brazil
⁶⁴ Collège de France, Lab. de Physique Corpusculaire, IN2P3-CNRS, 75231, Paris Cedex 05, France
⁶⁵ CERN, 1211, Geneva 23, Switzerland
⁶⁶ Institut de Recherches Subatomiques, IN2P3 - CNRS/ULP - BP20, 67037, Strasbourg Cedex, France
⁶⁷ DESY-Zeuthen, Platanenallee 6, 15735, Zeuthen, Germany
⁶⁸ Institute of Nuclear Physics, N.C.S.R. Demokritos, P.O. Box 60228, 15310, Athens, Greece
⁶⁹ Inst. of Phys. of the C.A.S. High Energy Physics Division, FZU, Na Slovance 2, 180 40, Praha 8, Czech Republic
⁷⁰ Dipartimento di Fisica, Università di Genova and INFN, Via Dodecaneso 33, 16146, Genova, Italy
⁷¹ Institut des Sciences Nucléaires, IN2P3-CNRS, Université de Grenoble 1, 38026, Grenoble Cedex, France
⁷² Helsinki Institute of Physics and Department of Physical Sciences, University of Helsinki, P.O. Box 64, 00014, Helsinki, Finland
⁷³ Head Post Office, Joint Institute for Nuclear Research, Dubna, P.O. Box 79, 101 000, Moscow, Russian Federation
⁷⁴ Institut für Experimentelle Kernphysik, Universität Karlsruhe, Postfach 6980, 76128, Karlsruhe, Germany
⁷⁵ Institute of Nuclear Physics PAN, Ul. Radzikowskiego 152, 31142, Krakow, Poland
⁷⁶ Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, 30055, Krakow, Poland
⁷⁷ Lab. de l’Accélérateur Linéaire, IN2P3-CNRS, Bât. 200, Université de Paris-Sud, 91405, Orsay Cedex, France
⁷⁸ School of Physics and Chemistry, University of Lancaster, Lancaster, LA1 4YB, UK
⁷⁹ LIP, IST, FCUL, Av. Elias Garcia, 14-1o, 1000, Lisboa Codex, Portugal
⁸⁰ Department of Physics, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX, UK
⁸¹ Dept. of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, G12 8QQ, UK
⁸² LPNHE, IN2P3-CNRS, Univ. Paris VI et VII, Tour 33 (RdC), 4 place Jussieu, 75252, Paris Cedex 05, France
⁸³ Department of Physics, University of Lund, Sölvegatan 14, 223 63, Lund, Sweden
⁸⁴ IPNL, IN2P3-CNRS, Université Claude Bernard de Lyon, 69622, Villeurbanne Cedex, France
⁸⁵ Dipartimento di Fisica, Università di Milano and INFN-MILANO, Via Celoria 16, 20133, Milan, Italy
⁸⁶ Dipartimento di Fisica, Univ. di Milano-Bicocca and INFN-MILANO, Piazza della Scienza 2, 20126, Milan, Italy
⁸⁷ IPNP of MFF, Charles Univ., Areal MFF, V Holesovickach 2, 180 00, Praha 8, Czech Republic
⁸⁸ NIKHEF, Postbus 41882, 1009 DB, Amsterdam, The Netherlands
⁸⁹ Physics Department, National Technical University, Zografou Campus, 15773, Athens, Greece
⁹⁰ Physics Department, University of Oslo, Blindern, 0316, Oslo, Norway
⁹¹ Dpto. Fisica, Univ. Oviedo, Avda. Calvo Sotelo s/n, 33007, Oviedo, Spain
⁹² Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK
⁹³ Dipartimento di Fisica, Università di Padova and INFN, Via Marzolo 8, 35131, Padua, Italy
⁹⁴ Rutherford Appleton Laboratory, Chilton, Didcot, OX11 OQX, UK
⁹⁵ Dipartimento di Fisica, Università di Roma II and INFN, Tor Vergata, 00173, Rome, Italy
⁹⁶ Dipartimento di Fisica, Università di Roma III and INFN, Via della Vasca Navale 84, 00146, Rome, Italy
⁹⁷ DAPNIA/Service de Physique des Particules, CEA-Saclay, 91191, Gif-sur-Yvette Cedex, France
⁹⁸ Instituto de Fisica de Cantabria (CSIC-UC), Avda. los Castros s/n, 39006, Santander, Spain
⁹⁹ Inst. for High Energy Physics, Serpukov, P.O. Box 35, Protvino, Moscow Region, Russian Federation
¹⁰⁰ J. Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
¹⁰¹ Laboratory for Astroparticle Physics, Nova Gorica Polytechnic, Kostanjeviska 16a, 5000, Nova Gorica, Slovenia
¹⁰² Department of Physics, University of Ljubljana, 1000, Ljubljana, Slovenia
¹⁰³ Fysikum, Stockholm University, Box 6730, 113 85, Stockholm, Sweden
¹⁰⁴ Dipartimento di Fisica Sperimentale, Università di Torino and INFN, Via P. Giuria 1, 10125, Turin, Italy
¹⁰⁵ Dipartimento di Fisica Teorica, Università di Torino and INFN, Sezione di Torino, Via Giuria 1, 10125, Turin, Italy
¹⁰⁶ Dipartimento di Fisica, Università di Trieste and INFN, Via A. Valerio 2, 34127, Trieste, Italy
¹⁰⁷ Istituto di Fisica, Università di Udine, 33100, Udine, Italy
¹⁰⁸ Univ. Federal do Rio de Janeiro, C.P. 68528, Cidade Univ., Ilha do Fundão, 21945-970, Rio de Janeiro, Brazil
¹⁰⁹ Department of Radiation Sciences, University of Uppsala, P.O. Box 535, 751 21, Uppsala, Sweden
¹¹⁰ IFIC, Valencia-CSIC, and D.F.A.M.N., U. de Valencia, Avda. Dr. Moliner 50, 46100, Burjassot (Valencia), Spain
¹¹¹ Institut für Hochenergiephysik, Österr. Akad. d. Wissensch., Nikolsdorfergasse 18, 1050, Vienna, Austria
¹¹² Inst. Nuclear Studies and University of Warsaw, Ul. Hoza 69, 00681, Warsaw, Poland
¹¹³ Fachbereich Physik, University of Wuppertal, Postfach 100 127, 42097, Wuppertal, Germany
¹¹⁴ III. Physikalisches Institut, RWTH, 52056, Aachen, Germany
¹¹⁵ National Institute for High Energy Physics, NIKHEF, and University of Amsterdam, 1009 DB, Amsterdam, The Netherlands
¹¹⁶ University of Michigan, Ann Arbor, MI, 48109, USA
¹¹⁷ Laboratoire d’Annecy-le-Vieux de Physique des Particules, LAPP, IN2P3-CNRS, BP 110, 74941, Annecy-le-Vieux CEDEX, France
¹¹⁸ Institute of Physics, University of Basel, 4056, Basel, Switzerland
¹¹⁹ Louisiana State University, Baton Rouge, LA, 70803, USA
¹²⁰ Institute of High Energy Physics, IHEP, 100039, Beijing, China
¹²¹ University of Bologna and INFN-Sezione di Bologna, 40126, Bologna, Italy
¹²² Tata Institute of Fundamental Research, Mumbai (Bombay), 400 005, India
¹²³ Northeastern University, Boston, MA, 02115, USA
¹²⁴ Institute of Atomic Physics and University of Bucharest, 76900, Bucharest, Romania
¹²⁵ Central Research Institute for Physics, Hungarian Academy of Sciences, 1525, Budapest 114, Hungary
¹²⁶ Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
¹²⁷ Panjab University, Chandigarh, 160 014, India
¹²⁸ KLTE-ATOMKI, 4010, Debrecen, Hungary
¹²⁹ UCD School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
¹³⁰ INFN Sezione di Firenze and University of Florence, 50125, Florence, Italy
¹³¹ European Laboratory for Particle Physics, CERN, 1211, Geneva 23, Switzerland
¹³² FBLJA Project, World Laboratory, 1211, Geneva 23, Switzerland
¹³³ University of Geneva, 1211, Geneva 4, Switzerland
¹³⁴ University of Hamburg, 22761, Hamburg, Germany
¹³⁵ Chinese University of Science and Technology, USTC, Hefei, Anhui, 230 029, China
¹³⁶ University of Lausanne, 1015, Lausanne, Switzerland
¹³⁷ Institut de Physique Nucléaire de Lyon, IN2P3-CNRS, Université Claude Bernard, 69622, Villeurbanne, France
¹³⁸ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, 28040, Madrid, Spain
¹³⁹ Florida Institute of Technology, Melbourne, FL, 32901, USA
¹⁴⁰ INFN-Sezione di Milano, 20133, Milan, Italy
¹⁴¹ Institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia
¹⁴² INFN-Sezione di Napoli and University of Naples, 80125, Naples, Italy
¹⁴³ Department of Physics, University of Cyprus, Nicosia, Cyprus
¹⁴⁴ Radboud University and NIKHEF, 6525 ED, Nijmegen, The Netherlands
¹⁴⁵ California Institute of Technology, Pasadena, CA, 91125, USA
¹⁴⁶ INFN-Sezione di Perugia and Università Degli Studi di Perugia, 06100, Perugia, Italy
¹⁴⁷ Nuclear Physics Institute, St. Petersburg, Russia
¹⁴⁸ Carnegie Mellon University, Pittsburgh, PA, 15213, USA
¹⁴⁹ INFN-Sezione di Napoli and University of Potenza, 85100, Potenza, Italy
¹⁵⁰ Princeton University, Princeton, NJ, 08544, USA
¹⁵¹ University of Californa, Riverside, CA, 92521, USA
¹⁵² INFN-Sezione di Roma and University of Rome, “La Sapienza”, 00185, Rome, Italy
¹⁵³ University and INFN Salerno, 84100, Salerno, Italy
¹⁵⁴ University of California, San Diego, CA, 92093, USA
¹⁵⁵ Central Lab. of Mechatronics and Instrumentation, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
¹⁵⁶ The Center for High Energy Physics, Kyungpook National University, 702-701, Taegu, Republic of Korea
¹⁵⁷ National Central University, Chung-Li, Taiwan
¹⁵⁸ Department of Physics, National Tsing Hua University, Tsing Hua, Taiwan
¹⁵⁹ Purdue University, West Lafayette, IN, 47907, USA
¹⁶⁰ Paul Scherrer Institut, PSI, 5232, Villigen, Switzerland
¹⁶¹ DESY, 15738, Zeuthen, Germany
¹⁶² Eidgenössische Technische Hochschule, ETH Zürich, 8093, Zürich, Switzerland
¹⁶³ School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
¹⁶⁴ Dipartimento di Fisica , Università di Bologna and INFN, 40126, Bologna, Italy
¹⁶⁵ Physikalisches Institut, Universität Bonn, 53115, Bonn, Germany
¹⁶⁶ Department of Physics, University of California, Riverside, CA, 92521, USA
¹⁶⁷ Cavendish Laboratory, Cambridge, CB3 0HE, UK
¹⁶⁸ Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
¹⁶⁹ CERN, European Organisation for Nuclear Research, 1211, Geneva 23, Switzerland
¹⁷⁰ Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
¹⁷¹ Fakultät für Physik, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
¹⁷² Physikalisches Institut, Universität Heidelberg, 69120, Heidelberg, Germany
¹⁷³ Department of Physics, Indiana University, Bloomington, IN, 47405, USA
¹⁷⁴ Queen Mary and Westfield College, University of London, London, E1 4NS, UK
¹⁷⁵ III Physikalisches Institut, Technische Hochschule Aachen, Sommerfeldstrasse 26–28, 52056, Aachen, Germany
¹⁷⁶ University College London, London, WC1E 6BT, UK
¹⁷⁷ Department of Physics, Schuster Laboratory, The University, Manchester, M13 9PL, UK
¹⁷⁸ Department of Physics, University of Maryland, College Park, MD, 20742, USA
¹⁷⁹ Laboratoire de Physique Nucléaire, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
¹⁸⁰ Department of Physics, University of Oregon, Eugene, OR, 97403, USA
¹⁸¹ CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
¹⁸² Department of Physics, Technion-Israel Institute of Technology, Haifa, 32000, Israel
¹⁸³ Department of Physics and Astronomy, Tel Aviv University, Tel Aviv, 69978, Israel
¹⁸⁴ International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan
¹⁸⁵ Kobe University, Kobe, 657-8501, Japan
¹⁸⁶ Particle Physics Department, Weizmann Institute of Science, Rehovot, 76100, Israel
¹⁸⁷ Institut für Experimentalphysik, Universität Hamburg/DESY, Notkestrasse 85, 22607, Hamburg, Germany
¹⁸⁸ Department of Physics, University of Victoria, P O Box 3055, Victoria, BC, V8W 3P6, Canada
¹⁸⁹ Department of Physics, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
¹⁹⁰ Department of Physics, University of Alberta, Edmonton, AB, T6G 2J1, Canada
¹⁹¹ Research Institute for Particle and Nuclear Physics, 1525, Budapest, P O Box 49, Hungary
¹⁹² Institute of Nuclear Research, 4001, Debrecen, P O Box 51, Hungary
¹⁹³ Sektion Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748, Garching, Germany
¹⁹⁴ Max-Planck-Institute für Physik, Föhringer Ring 6, 80805, München, Germany
¹⁹⁵ Department of Physics, Yale University, New Haven, CT, 06520, USA
¹⁹⁶ TRIUMF, Vancouver, V6T 2A3, Canada
¹⁹⁷ SLAC, Stanford, CA, 94309, USA
¹⁹⁸ Institute of Nuclear Research, Debrecen, Hungary
¹⁹⁹ Department of Experimental Physics, University of Debrecen, Debrecen, Hungary
²⁰⁰ MPI München, München, Germany
²⁰¹ Research Institute for Particle and Nuclear Physics, Budapest, Hungary
²⁰² Dept. of Physics, University of Liverpool, Liverpool, L69 3BX, UK
²⁰³ Dept. Physics, University of Illinois, Urbana-Champaign, USA
²⁰⁴ Manchester University, Manchester, UK
²⁰⁵ Dept. of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
²⁰⁶ Dept. of Physics, University of Toronto, Toronto, Canada
²⁰⁷ Bergische Universität, Wuppertal, Germany
²⁰⁸ University of Mining and Metallurgy, Cracow, Poland
²⁰⁹ University of California, San Diego, USA
²¹⁰ The University of Melbourne, Victoria, Australia
²¹¹ IPHE Université de Lausanne, 1015, Lausanne, Switzerland
²¹² IEKP Universität Karlsruhe, Karlsruhe, Germany
²¹³ Physics Department, University of Antwerpen, 2610, Antwerpen, Belgium
²¹⁴ University of Nijmegen, Nijmegen, The Netherlands
²¹⁵ High Energy Accelerator Research Organisation (KEK), Tsukuba, Ibaraki, Japan
²¹⁶ University of Pennsylvania, Philadelphia, Pennsylvania, USA
²¹⁷ TRIUMF, Vancouver, Canada
²¹⁸ DESY-Zeuthen, Zeuthen, Germany
²¹⁹ CERN, 1211, Geneva 23, Switzerland
²²⁰ DESY, Hamburg, Germany
²²¹ Departamento de Fisica Teorica, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza, Spain
²²² Dept. of Physics, CERN TH division, 1211, Geneva 23, Switzerland
²²³ Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
²²⁴ Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE, UK

Received: 17 January 2006
Revised: 12 April 2006
Published online: 18 July 2006

Abstract

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of “benchmark” models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter cosβ and, in some scenarios, on the masses of neutral Higgs bosons.