Eur. Phys. J. C (2006) 48: 699-714
https://doi.org/10.1140/epjc/s10052-006-0028-2

Experimental Physics

Tau lepton production in ep collisions at HERA

¹ I. Physikalisches Institut, RWTH, Aachen, Germany
² School of Physics and Astronomy, University of Birmingham, Birmingham, UK
³ Inter-University Institute for High Energies ULB-VUB, Brussels, Belgium
⁴ Universiteit Antwerpen, Antwerpen, Belgium
⁵ Rutherford Appleton Laboratory, Chilton, Didcot, UK
⁶ Institute for Nuclear Physics, Cracow, Poland
⁷ Institut für Physik, Universität Dortmund, Dortmund, Germany
⁸ Joint Institute for Nuclear Research, Dubna, Russia
⁹ CEA, DSM/DAPNIA, CE-Saclay, Gif-sur-Yvette, France
¹⁰ DESY, Hamburg, Germany
¹¹ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
¹² Max-Planck-Institut für Kernphysik, Heidelberg, Germany
¹³ Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
¹⁴ Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
¹⁵ Institut für Experimentelle und Angewandte Physik, Universität Kiel, Kiel, Germany
¹⁶ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
¹⁷ Department of Physics, University of Lancaster, Lancaster, UK
¹⁸ Department of Physics, University of Liverpool, Liverpool, UK
¹⁹ Queen Mary and Westfield College, London, UK
²⁰ Physics Department, University of Lund, Lund, Sweden
²¹ Physics Department, University of Manchester, Manchester, UK
²² CPPM, CNRS/IN2P3, Univ. Mediterranee, Marseille, France
²³ Departamento de Fisica Aplicada, CINVESTAV, Merida, Yucatan, Mexico
²⁴ Departamento de Fisica, CINVESTAV, Merida, Mexico
²⁵ Institute for Theoretical and Experimental Physics, Moscow, Russia
²⁶ Lebedev Physical Institute, Moscow, Russia
²⁷ Max-Planck-Institut für Physik, München, Germany
²⁸ LAL, Université de Paris-Sud 11, IN2P3-CNRS, Orsay, France
²⁹ LLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
³⁰ LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France
³¹ Faculty of Science, University of Montenegro, Podgorica, Serbia and Montenegro
³² Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic
³³ Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
³⁴ Dipartimento di Fisica, Università di Roma Tre and INFN Roma 3, Roma, Italy
³⁵ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
³⁶ Paul Scherrer Institut, Villigen, Switzerland
³⁷ Fachbereich C, Universität Wuppertal, Wuppertal, Germany
³⁸ Yerevan Physics Institute, Yerevan, Armenia
³⁹ DESY, Zeuthen, Germany
⁴⁰ Institut für Teilchenphysik, ETH, Zürich, Switzerland
⁴¹ Physik-Institut, Universität Zürich, Zürich, Switzerland
⁴² Physics Department, National Technical University, Zografou Campus, 15773, Athens, Greece
⁴³ Rechenzentrum, Universität Wuppertal, Wuppertal, Germany
⁴⁴ University of P.J. Šafárik, Košice, Slovak Republic
⁴⁵ CERN, Geneva, Switzerland
⁴⁶ Max-Planck-Institut für Physik, München, Germany
⁴⁷ Comenius University, Bratislava, Slovak Republic

^* e-mail: eperez@hep.saclay.cea.fr

Received: 13 April 2006
Revised: 20 July 2006
Published online: 24 October 2006

Abstract

The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994–2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.