Eur. Phys. J. C (2012) 72: 2076
https://doi.org/10.1140/epjc/s10052-012-2076-0

Regular Article - Experimental Physics

Search for charged Higgs bosons in e⁺e⁻ collisions at

¹ School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
² Dipartimento di Fisica dell’ Università di Bologna and INFN, 40126, Bologna, Italy
³ Physikalisches Institut, Universität Bonn, 53115, Bonn, Germany
⁴ Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA
⁵ Cavendish Laboratory, Cambridge, CB3 0HE, UK
⁶ Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
⁷ CERN, European Organisation for Nuclear Research, 1211, Geneva 23, Switzerland
⁸ Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
⁹ Fakultät für Physik, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
¹⁰ Physikalisches Institut, Universität Heidelberg, 69120, Heidelberg, Germany
¹¹ Department of Physics, Indiana University, Bloomington, IN, 47405, USA
¹² Queen Mary and Westfield College, University of London, London, E1 4NS, UK
¹³ III Physikalisches Institut, Technische Hochschule Aachen, Sommerfeldstrasse 26-28, 52056, Aachen, Germany
¹⁴ University College London, London, WC1E 6BT, UK
¹⁵ School of Physics and Astronomy, Schuster Laboratory, The University of Manchester, Manchester, M13 9PL, UK
¹⁶ Department of Physics, University of Maryland, College Park, MD, 20742, USA
¹⁷ Laboratoire de Physique Nucléaire, Université de Montréal, Montréal, Québec, H3C 3J7, Canada
¹⁸ Department of Physics, University of Oregon, Eugene, OR, 97403, USA
¹⁹ Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
²⁰ Department of Physics, Technion-Israel Institute of Technology, Haifa, 32000, Israel
²¹ Department of Physics and Astronomy, Tel Aviv University, Tel Aviv, 69978, Israel
²² International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan
²³ Kobe University, Kobe, 657-8501, Japan
²⁴ Particle Physics Department, Weizmann Institute of Science, Rehovot, 76100, Israel
²⁵ Institut für Experimentalphysik, Universität Hamburg/DESY, Notkestrasse 85, 22607, Hamburg, Germany
²⁶ Department of Physics, University of Victoria, PO Box 3055, Victoria, BC, V8W 3P6, Canada
²⁷ Department of Physics, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
²⁸ Department of Physics, University of Alberta, Edmonton, AB, T6G 2J1, Canada
²⁹ Research Institute for Particle and Nuclear Physics, 1525, Budapest, PO Box 49, Hungary
³⁰ Institute of Nuclear Research, 4001, Debrecen, PO Box 51, Hungary
³¹ Sektion Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748, Garching, Germany
³² Max-Planck-Institute für Physik, Föhringer Ring 6, 80805, München, Germany
³³ Department of Physics, Yale University, New Haven, CT, 06520, USA

^* e-mail: Pippa.Wells@cern.ch

Received: 14 October 2008
Revised: 22 June 2012
Published online: 24 July 2012

Abstract

A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at , corresponding to an integrated luminosity of approximately 600 pb⁻¹. Charged Higgs bosons are assumed to be pair-produced and to decay into , τν _τ or AW^±. No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are derived by combining these results with previous searches at lower energies. Under the assumption , motivated by general 2HDM type II models, excluded areas on the plane are presented and charged Higgs bosons are excluded up to a mass of 76.3 GeV at 95 % confidence level, independent of the branching ratio BR(H^±→τν _τ ). A scan of the 2HDM type I model parameter space is performed and limits on the Higgs-boson masses and m _A are presented for different choices of tanβ.