Eur. Phys. J. C (1998) 5: 19-40
https://doi.org/10.1007/s100529800931

Experimental physics

A search for neutral Higgs bosons in the MSSM and models with two scalar field doublets

¹⁰ School of Physics and Astronomy, University of Birmingham, B15 2TT, Birmingham, UK
⁷ Dipartimento di Fisica dell’ Università di Bologna and INFN, 1-40126, Bologna, Italy
¹⁵ Physikalisches Institut, Universität Bonn, D-53115, Bonn, Germany
²⁶ Department of Physics, University of California, 92521, Riverside, CA, USA
⁴ Cavendish Laboratory, CB3 OHE, Cambridge, UK
²³ Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, K1S 5B6, Ottawa, Ontario, Canada
³¹ Centre for Research in Particle Physics, Carleton University, K1S 5B6, Ottawa, Ontario, Canada
¹ CERN, European Organisation for Particle Physics, CH-1211, Geneva 23, Switzerland
⁵ Enrico Fermi Institute and Department of Physics, University of Chicago, 60637, Chicago, IL, USA
²⁰ Fakultät für Physik, Albert Ludwigs Universität, D-79104, Freiburg, Germany
²¹ Physikalisches Institut, Universität Heidelberg, D-69120, Heidelberg, Germany
⁶ Department of Physics, Indiana University, Swain Hall West 117, 47405, Bloomington, IN, USA
²⁴ Queen Mary and Westfield College, University of London, El 4NS, London, UK
¹⁶ Technische Hochschule Aachen, III Physikalisches Institut, Sommerfeldstrasse 26-28, D-52056, Aachen, Germany
¹⁸ University College London, WC1E 6BT, London, UK
³ Department of Physics, Schuster Laboratory, The University, M13 9PL, Manchester, UK
¹⁴ Department of Physics, University of Maryland, 20742, College Park, MD, USA
¹² Laboratoire de Physique Nucléaire, Université de Montréal, H3C 3J7, Montréal, Quebec, Canada
³⁷ Department of Physics, University of Oregon, 97403, Eugene, OR, USA
¹⁷ Rutherford Appleton Laboratory, OX11 OQX, Chilton, Didcot, Oxfordshire, UK
²⁷ Department of Physics, Technion-Israel Institute of Technology, 32000, Haifa, Israel
² Department of Physics and Astronomy, Tel Aviv University, 69978, Tel Aviv, Israel
⁸ International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, 113, Tokyo, Japan
⁹ Kobe University, 657, Kobe, Japan
³⁴ Institute of Physical and Environmental Sciences, Brunel University, UB8 3PH, Uxbridge, Middlesex, UK
³² Particle Physics Department, Weizmann Institute of Science, 76100, Rehovot, Israel
¹⁹ Universität Hamburg/DESY, II Institut für Experimental Physik, Notkestrasse 85, D-22607, Hamburg, Germany
³⁵ Department of Physics, University of Victoria, P 0 Box 3055, V8W 3P6, Victoria, BC, Canada
¹¹ Department of Physics, University of British Columbia, V6T 1Z1, Vancouver, BC, Canada
²⁸ Department of Physics, University of Alberta, T6G 2J1, Edmonton, AB, Canada
³⁸ Dept of Physics, Duke University, 27708-0305, Durham, NC, USA
³³ Research Institute for Particle and Nuclear Physics, P O Box 49, H-1525, Budapest, Hungary
²⁹ Institute of Nuclear Research, P O Box 51, H-4001, Debrecen, Hungary
²² Ludwigs-Maximilians-Universität München, Sektion Physik, Am Coulombwall 1, D-85748, Garching, Germany
¹³ TRIUMF, V6T 2A3, Vancouver, Canada
²⁵ Royal Society University Research Fellow, UK
³⁶ Institute of Nuclear Research, Debrecen, Hungary
³⁰ Department of Experimental Physics, Lajos Kossuth University, Debrecen, Hungary
⁴⁰ Department of Physics, New York University, 1003, NY, USA

Received: 20 February 1998
Published online: 16 September 2013

Abstract

A search is described for the neutral Higgs bosons h⁰ and A⁰ predicted by models with two scalar field doublets and, in particular, the Minimal Supersymmetric Standard Model (MSSM). The search in the Z⁰h⁰ and h⁰A⁰ production channels is based on data corresponding to an integrated luminosity of 25 pb⁻¹ from e⁺e⁻ collisions at centre-of-mass energies between 130 and 172 GeV collected with the OPAL detector at LEP. The observation of a number of candidates consistent with Standard Model background expectations is used in combination with earlier results from data collected at the Z⁰ resonance to set limits on m_h and m_a in general models with two scalar field doublets and in the MSSM. For example, in the MSSM, for tan β > 1, minimal and maximal scalar top quark mixing and soft SUSY-breaking masses of 1 TeV, the 95% confidence level limits m_h > 59.0 GeV and m_a > 59.5 GeV are obtained. For the first time, the MSSM parameter space is explored in a detailed scan.