Eur. Phys. J. C (2006) 47: 295-307
https://doi.org/10.1140/epjc/s2006-02581-y

Experimental Physics

Measurement of the strong coupling α_S from four-jet observables in e⁺e^- annihilation

¹ School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
² Dipartimento di Fisica, Università di Bologna and INFN, 40126, Bologna, Italy
³ Physikalisches Institut, Universität Bonn, 53115, Bonn, Germany
⁴ Department of Physics, 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 Department of Physics, Schuster Laboratory, The University, 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 CCLRC 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 Particle Physics Department, Weizmann Institute of Science, Rehovot, 76100, Israel
²⁴ Institut für Experimentalphysik, Universität Hamburg/DESY, Notkestrasse 85, 22607, Hamburg, Germany
²⁵ Department of Physics, University of Victoria, P.O.Box 3055, Victoria, BC, V8W 3P6, Canada
²⁶ Department of Physics, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
²⁷ Department of Physics, University of Alberta, Edmonton, AB, T6G 2J1, Canada
²⁸ Research Institute for Particle and Nuclear Physics, 1525, Budapest, P.O. Box 49, Hungary
²⁹ Institute of Nuclear Research, 4001, Debrecen, P.O. Box 51, Hungary
³⁰ Sektion Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748, Garching, Germany
³¹ Max-Planck-Institute für Physik, Föhringer Ring 6, 80805, München, Germany
³² Department of Physics, Yale University, New Haven, CT, 06520, USA

Received: 25 November 2005
Published online: 30 June 2006

Abstract

Data from e⁺e^- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter y_cut. The four-jet rate is compared to next-to-leading order calculations that include the resummation of large logarithms. The strong coupling measured from the four-jet rate is in agreement with the world average. Next-to-leading order fits to the D-parameter and thrust minor event-shape observables are also performed for the first time. We find consistent results, but with significantly larger theoretical uncertainties.