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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.
Details
1 Physikalisches Institut, RWTH-Aachen, Aachen, Germany
2 Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, Annecy-le-Vieux Cedex, France
3 Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain
4 Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), Spain; Universitat de Barcelona, Barcelona, Spain
5 Dipartimento di Fisica, INFN Sezione di Bari, Bari, Italy
6 Dipartimento di Fisica, INFN Sezione di Bari, Bari, Italy; Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, Palermo, Italy
7 Dipartimento di Fisica, INFN Sezione di Bari, Bari, Italy; Dipartimento di Fisica di Catania and INFN Sezione di Catania, Catania, Italy
8 Institute of High Energy Physics, Academia Sinica, Beijing, P.R. China
9 European Laboratory for Particle Physics (CERN), Geneva 23, Switzerland
10 European Laboratory for Particle Physics (CERN), Geneva 23, Switzerland; SLAC, Stanford, CA, USA
11 European Laboratory for Particle Physics (CERN), Geneva 23, Switzerland; Institut Inter-universitaire des hautes Energies (IIHE), CP 230, Université Libre de Bruxelles, Bruxelles, Belgium
12 European Laboratory for Particle Physics (CERN), Geneva 23, Switzerland; Liverpool University, Liverpool, UK
13 European Laboratory for Particle Physics (CERN), Geneva 23, Switzerland; Fermilab, Batavia, IL, USA
14 Laboratoire de Physique Corpusculaire, Université Blaise Pascal, IN2P3-CNRS, Aubière, France
15 Laboratoire de Physique Corpusculaire, Université Blaise Pascal, IN2P3-CNRS, Aubière, France; Groupe d’ Astroparticules de Montpellier, Université de Montpellier II, Montpellier, France
16 Niels Bohr Institute, Copenhagen, Denmark
17 Nuclear Research Center Demokritos (NRCD), Attiki, Greece
18 Laoratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau Cedex, France; Departement de Physique Corpusculaire, Université de Genève, Genève 4, Switzerland
19 Laoratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau Cedex, France
20 Dipartimento di Fisica, Università di Firenze, INFN Sezione di Firenze, Firenze, Italy
21 Laboratori Nazionali dell’INFN (LNF-INFN), Frascati, Italy
22 Department of Physics and Astronomy, University of Glasgow, Glasgow, UK
23 Utah Valley State College, Orem, UT, U.S.A.
24 Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany; Department of Physics, University of Florida, Gainesville, Florida, USA
25 Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany; BNP Paribas, Frankfurt am Main, Germany
26 Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
27 Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany; SAP AG, Walldorf, Germany
28 Department of Physics, Imperial College, London, UK
29 Department of Physics, Imperial College, London, UK; CERN, Geneva 23, Switzerland
30 Institut für Experimentalphysik, Universität Innsbruck, Innsbruck, Austria
31 Department of Physics, University of Lancaster, Lancaster, UK
32 Institut de Physique Nucléaire, Département de Physique, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
33 Institut für Physik, Universität Mainz, Mainz, Germany
34 Centre de Physique des Particules de Marseille, Univ Méditerranée, IN2P3-CNRS, Marseille, France
35 Dipartimento di Fisica, Università di Milano e INFN Sezione di Milano, Milano, Italy
36 Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, München, Germany
37 Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, München, Germany; Henryk Niewodnicznski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
38 Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, München, Germany; CERN, Geneva 23, Switzerland
39 Laboratoire de l’Accélérateur Linéaire, Université de Paris-Sud, IN2P3-CNRS, Orsay Cedex, France
40 Laboratoire de l’Accélérateur Linéaire, Université de Paris-Sud, IN2P3-CNRS, Orsay Cedex, France; Groupe d’Astroparticules de Montpellier, Université de Montpellier II, Montpellier, France
41 Dipartimento di Fisica, Università, INFN Sezione di Pisa, e Scuola Normale Superiore, Pisa, Italy
42 Department of Physics, Royal Holloway & Bedford New College, University of London, Egham, Surrey, UK
43 Particle Physics Dept., Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK
44 CEA, DAPNIA/Service de Physique des Particules, CE-Saclay, Gif-sur-Yvette Cedex, France
45 Institute for Particle Physics, University of California at Santa Cruz, Santa Cruz, CA, USA
46 Department of Physics, University of Sheffield, Sheffield, UK
47 Fachbereich Physik, Universität Siegen, Siegen, Germany
48 Dipartimento di Fisica, Università di Trieste e INFN Sezione di Trieste, Trieste, Italy
49 Experimental Elementary Particle Physics, University of Washington, Seattle, WA, U.S.A.
50 Department of Physics, University of Wisconsin, Madison, WI, USA
51 Department of Physics, University of Wisconsin, Madison, WI, USA; Department of Physics, Tsinghua University, Beijing, P.R. China
52 Institute for Particle Physics, ETH Hönggerberg, Zürich, Switzerland
53 LPNHE, IN2P3-CNRS, Univ. Paris VI et VII, Tour 33 (RdC), Paris Cedex 05, France
54 LIP, IST, FCUL, Lisboa Codex, Portugal
55 Institut für Hochenergiephysik, Österr. Akad. d. Wissensch., Vienna, Austria
56 Institute of Nuclear Physics, N.C.S.R. Demokritos, Athens, Greece
57 Institut für Experimentelle Kernphysik, Universität Karlsruhe, Karlsruhe, Germany
58 Physics Department, Universiteit Antwerpen, Antwerpen, Belgium; IIHE, ULB-VUB, Brussels, Belgium; Faculté des Sciences, Univ. de l’Etat Mons, Mons, Belgium
59 CERN, Geneva 23, Switzerland
60 Department of Physics, University of Liverpool, Liverpool, UK
61 Dipartimento di Fisica, Univ. di Milano-Bicocca and INFN-MILANO, Milan, Italy
62 Dipartimento di Fisica Sperimentale, Università di Torino and INFN, Turin, Italy
63 Univ. Federal do Rio de Janeiro, Rio de Janeiro, Brazil
64 Dipartimento di Fisica, Università di Padova and INFN, Padua, Italy
65 Dipartimento di Fisica, Università di Milano and INFN-MILANO, Milan, Italy
66 Institut des Sciences Nucléaires, IN2P3-CNRS, Université de Grenoble 1, Grenoble Cedex, France
67 Department of Physics, University of Lund, Lund, Sweden
68 Fysikum, Stockholm University, Stockholm, Sweden
69 Dipartimento di Fisica Teorica, Università di Torino and INFN, Sezione di Torino, Turin, Italy
70 Lab. de l’Accélérateur Linéaire, IN2P3-CNRS, Bât. 200, Université de Paris-Sud, Orsay Cedex, France
71 IPNL, IN2P3-CNRS, Université Claude Bernard de Lyon, Villeurbanne Cedex, France
72 Head Post Office, Joint Institute for Nuclear Research, Dubna, Moscow, Russian Federation
73 Dipartimento di Fisica, Università di Roma III and INFN, Rome, Italy
74 Fachbereich Physik, University of Wuppertal, Wuppertal, Germany
75 Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brazil; Depto. de Física, Pont. Univ. Católica, Rio de Janeiro, Brazil; Inst. de Física, Univ. Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
76 Physics Department, National Technical University, Athens, Greece
77 Dipartimento di Fisica, Università di Bologna and INFN, Bologna, Italy
78 DAPNIA/Service de Physique des Particules, CEA-Saclay, Gif-sur-Yvette Cedex, France
79 Institut de Recherches Subatomiques, IN2P3 - CNRS/ULP - BP20, Strasbourg Cedex, France
80 NIKHEF, Amsterdam, The Netherlands
81 Inst. Nuclear Studies and University of Warsaw, Warsaw, Poland
82 School of Physics and Chemistry, University of Lancaster, Lancaster, UK
83 Department of Radiation Sciences, University of Uppsala, Uppsala, Sweden
84 J. Stefan Institute, Ljubljana, Slovenia; Laboratory for Astroparticle Physics, Nova Gorica Polytechnic, Nova Gorica, Slovenia; Department of Physics, University of Ljubljana, Ljubljana, Slovenia
85 Department of Physics, University of Oxford, Oxford, UK
86 Institute of Nuclear Physics PAN, Krakow, Poland
87 Collège de France, Lab. de Physique Corpusculaire, IN2P3-CNRS, Paris Cedex 05, France
88 Dipartimento di Fisica, Università di Roma II and INFN, Rome, Italy
89 Inst. for High Energy Physics, Serpukov, Protvino, Moscow Region, Russian Federation
90 Dipartimento di Fisica, Università di Genova and INFN, Genova, Italy
91 Dipartimento di Fisica, Università di Trieste and INFN, Trieste, Italy; Istituto di Fisica, Università di Udine, Udine, Italy
92 IFIC, Valencia-CSIC, and D.F.A.M.N., U. de Valencia, Burjassot (Valencia), Spain
93 Rutherford Appleton Laboratory, Chilton, Didcot, UK
94 Dpto. Fisica, Univ. Oviedo, Oviedo, Spain
95 Fachbereich Physik, University of Wuppertal, Wuppertal, Germany; CERN, Geneva 23, Switzerland
96 Department of Physics, University of Bergen, Bergen, Norway
97 Institute of Nuclear Physics, N.C.S.R. Demokritos, Athens, Greece; Physics Laboratory, University of Athens, Athens, Greece
98 Instituto de Fisica de Cantabria (CSIC-UC), Santander, Spain
99 CERN, Geneva 23, Switzerland; Inst. Nuclear Studies and University of Warsaw, Warsaw, Poland
100 Physics Department, University of Oslo, Oslo, Norway
101 CERN, Geneva 23, Switzerland; J. Stefan Institute, Ljubljana, Slovenia; Laboratory for Astroparticle Physics, Nova Gorica Polytechnic, Nova Gorica, Slovenia; Department of Physics, University of Ljubljana, Ljubljana, Slovenia
102 Physics Laboratory, University of Athens, Athens, Greece
103 Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
104 IPNP of MFF, Charles Univ., Areal MFF, Praha 8, Czech Republic
105 Inst. of Phys. of the C.A.S. High Energy Physics Division, FZU, Praha 8, Czech Republic
106 CERN, Geneva 23, Switzerland; DESY-Zeuthen, Zeuthen, Germany
107 Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Krakow, Poland
108 Head Post Office, Joint Institute for Nuclear Research, Dubna, Moscow, Russian Federation; Institut de Recherches Subatomiques, IN2P3 - CNRS/ULP - BP20, Strasbourg Cedex, France
109 Helsinki Institute of Physics and Department of Physical Sciences, University of Helsinki, Helsinki, Finland
110 Dept. of Physics and Astronomy, Kelvin Building, University of Glasgow, Glasgow, UK
111 Physics Department, Universiteit Antwerpen, Antwerpen, Belgium; IIHE, ULB-VUB, Brussels, Belgium; Faculté des Sciences, Univ. de l’Etat Mons, Mons, Belgium; Head Post Office, Joint Institute for Nuclear Research, Dubna, Moscow, Russian Federation
112 University of Geneva, Geneva 4, Switzerland
113 INFN Sezione di Firenze and University of Florence, Florence, Italy
114 Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, Madrid, Spain
115 University of Lausanne, Lausanne, Switzerland
116 European Laboratory for Particle Physics, CERN, Geneva 23, Switzerland
117 INFN-Sezione di Napoli and University of Naples, Naples, Italy
118 Eidgenössische Technische Hochschule, ETH Zürich, Zürich, Switzerland
119 Louisiana State University, Baton Rouge, LA, USA; Nuclear Physics Institute, St. Petersburg, Russia
120 University of Bologna and INFN-Sezione di Bologna, Bologna, Italy
121 Institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia
122 University of Michigan, Ann Arbor, MI, USA
123 Tata Institute of Fundamental Research, Mumbai (Bombay), India
124 INFN-Sezione di Roma and University of Rome, “La Sapienza”, Rome, Italy
125 Florida Institute of Technology, Melbourne, FL, USA
126 National Institute for High Energy Physics, NIKHEF, and University of Amsterdam, Amsterdam, The Netherlands
127 Laboratoire d’Annecy-le-Vieux de Physique des Particules, LAPP, IN2P3-CNRS, Annecy-le-Vieux CEDEX, France
128 Eidgenössische Technische Hochschule, ETH Zürich, Zürich, Switzerland; Paul Scherrer Institut, PSI, Villigen, Switzerland
129 Purdue University, West Lafayette, IN, USA
130 INFN-Sezione di Perugia and Università Degli Studi di Perugia, Perugia, Italy
131 Massachusetts Institute of Technology, Cambridge, MA, USA
132 Carnegie Mellon University, Pittsburgh, PA, USA
133 III. Physikalisches Institut, RWTH, Aachen, Germany
134 Central Research Institute for Physics, Hungarian Academy of Sciences, Budapest 114, Hungary
135 University of California, San Diego, CA, USA
136 INFN-Sezione di Napoli and University of Potenza, Potenza, Italy
137 National Central University, Chung-Li, Taiwan
138 Institut de Physique Nucléaire de Lyon, IN2P3-CNRS, Université Claude Bernard, Villeurbanne, France
139 Institute of High Energy Physics, IHEP, Beijing, China
140 Chinese University of Science and Technology, USTC, Anhui, China
141 University and INFN Salerno, Salerno, Italy
142 University of Californa, Riverside, CA, USA
143 Paul Scherrer Institut, PSI, Villigen, Switzerland
144 Princeton University, Princeton, NJ, USA
145 Northeastern University, Boston, MA, USA
146 California Institute of Technology, Pasadena, CA, USA
147 Nuclear Physics Institute, St. Petersburg, Russia
148 Radboud University and NIKHEF, Nijmegen, The Netherlands
149 INFN-Sezione di Milano, Milan, Italy
150 Institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia; Massachusetts Institute of Technology, Cambridge, MA, USA
151 UCD School of Physics, University College Dublin, Dublin 4, Ireland
152 Institute of Physics, University of Basel, Basel, Switzerland
153 Panjab University, Chandigarh, India
154 The Center for High Energy Physics, Kyungpook National University, Taegu, Republic of Korea
155 Massachusetts Institute of Technology, Cambridge, MA, USA; Institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia
156 DESY, Zeuthen, Germany
157 Louisiana State University, Baton Rouge, LA, USA
158 European Laboratory for Particle Physics, CERN, Geneva 23, Switzerland; INFN-Sezione di Napoli and University of Naples, Naples, Italy
159 Institute of Atomic Physics and University of Bucharest, Bucharest, Romania
160 KLTE-ATOMKI, Debrecen, Hungary
161 Department of Physics, University of Cyprus, Nicosia, Cyprus
162 University of Hamburg, Hamburg, Germany
163 Central Lab. of Mechatronics and Instrumentation, Bulgarian Academy of Sciences, Sofia, Bulgaria
164 Carnegie Mellon University, Pittsburgh, PA, USA; Institute of Theoretical and Experimental Physics, ITEP, Moscow, Russia
165 Department of Physics, National Tsing Hua University, Tsing Hua, Taiwan
166 University of Bologna and INFN-Sezione di Bologna, Bologna, Italy; European Laboratory for Particle Physics, CERN, Geneva 23, Switzerland; FBLJA Project, World Laboratory, Geneva 23, Switzerland
167 Dipartimento di Fisica , Università di Bologna and INFN, Bologna, Italy
168 Cavendish Laboratory, Cambridge, UK
169 Physikalisches Institut, Universität Bonn, Bonn, Germany; CERN, Geneva 23, Switzerland
170 Department of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
171 Department of Physics, Schuster Laboratory, The University, Manchester, UK
172 Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago, IL, USA
173 School of Physics and Astronomy, University of Birmingham, Birmingham, UK
174 International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan; Kobe University, Kobe, Japan
175 Department of Physics, University of British Columbia, Vancouver, BC, Canada
176 Laboratoire de Physique Nucléaire, Université de Montréal, Montréal, Québec, Canada; TRIUMF, Vancouver, Canada
177 Department of Physics, University of Victoria, Victoria, BC, Canada
178 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; The University of Melbourne, Victoria, Australia
179 Max-Planck-Institute für Physik, München, Germany
180 Institut für Experimentalphysik, Universität Hamburg/DESY, Hamburg, Germany; SLAC, Stanford, CA, USA
181 Institut für Experimentalphysik, Universität Hamburg/DESY, Hamburg, Germany
182 CCLRC Rutherford Appleton Laboratory, Oxfordshire, UK
183 Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada
184 Department of Physics, University of California, Riverside, CA, USA
185 Sektion Physik, Ludwig-Maximilians-Universität München, Garching, Germany
186 Fakultät für Physik, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
187 Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
188 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland
189 Queen Mary and Westfield College, University of London, London, UK
190 Department of Physics, University of Maryland, College Park, MD, USA
191 Research Institute for Particle and Nuclear Physics, Budapest, Hungary
192 Department of Physics, Technion-Israel Institute of Technology, Haifa, Israel
193 Department of Physics, Indiana University, Bloomington, IN, USA; University of Nijmegen, Nijmegen, The Netherlands
194 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; Physics Department, University of Antwerpen, Antwerpen, Belgium
195 Institute of Nuclear Research, Debrecen, Hungary
196 Particle Physics Department, Weizmann Institute of Science, Rehovot, Israel
197 Department of Physics, Indiana University, Bloomington, IN, USA
198 Physikalisches Institut, Universität Bonn, Bonn, Germany
199 Research Institute for Particle and Nuclear Physics, Budapest, Hungary; Institute of Nuclear Research, Debrecen, Hungary
200 Laboratoire de Physique Nucléaire, Université de Montréal, Montréal, Québec, Canada
201 Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada; Dept. Physics, University of Illinois, Urbana-Champaign, USA
202 International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan; Kobe University, Kobe, Japan; High Energy Accelerator Research Organisation (KEK), Tsukuba, Ibaraki, Japan
203 Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada; Dept. of Physics, University of Toronto, Toronto, Canada
204 III Physikalisches Institut, Technische Hochschule Aachen, Aachen, Germany
205 University of California, San Diego, USA
206 Department of Physics, University of British Columbia, Vancouver, BC, Canada; TRIUMF, Vancouver, Canada
207 Bergische Universität, Wuppertal, Germany
208 Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, Canada; TRIUMF, Vancouver, Canada
209 University College London, London, UK
210 International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan; Kobe University, Kobe, Japan; University of Pennsylvania, Philadelphia, Pennsylvania, USA
211 Department of Physics, Yale University, New Haven, CT, USA
212 Department of Physics, University of California, Riverside, CA, USA; Research Institute for Particle and Nuclear Physics, Budapest, Hungary
213 Department of Physics, University of Alberta, Edmonton, AB, Canada
214 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; University of Mining and Metallurgy, Cracow, Poland
215 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; IEKP Universität Karlsruhe, Karlsruhe, Germany
216 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; Manchester University, Manchester, UK
217 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; DESY, Hamburg, Germany
218 III Physikalisches Institut, Technische Hochschule Aachen, Aachen, Germany; MPI München, München, Germany
219 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; Dept. of Physics, University of Liverpool, Liverpool, UK
220 Physikalisches Institut, Universität Bonn, Bonn, Germany; DESY-Zeuthen, Zeuthen, Germany
221 Department of Physics, University of Oregon, Eugene, OR, USA
222 Institute of Nuclear Research, Debrecen, Hungary; Department of Experimental Physics, University of Debrecen, Debrecen, Hungary
223 CERN, European Organisation for Nuclear Research, Geneva 23, Switzerland; IPHE Université de Lausanne, Lausanne, Switzerland
224 Department of Physics, Schuster Laboratory, The University, Manchester, UK; Dept. of Physics and Astronomy, University of Kansas, Lawrence, KS, USA
225 Departamento de Fisica Teorica, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain; Dept. of Physics, CERN TH division, Geneva 23, Switzerland
226 Department of Physics and Astronomy, University of Manchester, Manchester, UK
227 Institute for Particle Physics Phenomenology, University of Durham, Durham, UK





