Eur. Phys. J. C (2007) 51: 787-824
https://doi.org/10.1140/epjc/s10052-007-0361-0

Regular Article - Experimental Physics

Measurement of the production of charged pions by protons on a tantalum target

¹ Università degli Studi e Sezione INFN, Bari, Italy
² Rutherford Appleton Laboratory, Chilton, Didcot, UK
³ Institut für Physik, Universität Dortmund, Dortmund, Germany
⁴ Joint Institute for Nuclear Research, JINR, Dubna, Russia
⁵ Università degli Studi e Sezione INFN, Ferrara, Italy
⁶ CERN, Geneva, Switzerland
⁷ Section de Physique, Université de Genève, Genève, Switzerland
⁸ Institut für Physik, Forschungszentrum, Karlsruhe, Germany
⁹ University of Kyoto, Kyoto, Japan
¹⁰ Laboratori Nazionali di Legnaro dell’ INFN, Legnaro, Italy
¹¹ Los Alamos National Laboratory, Los Alamos, USA
¹² Institut de Physique Nucléaire, UCL, Louvain-la-Neuve, Belgium
¹³ Institute for Nuclear Research, Moscow, Russia
¹⁴ Università degli Studi e Sezione INFN Milano Bicocca, Milano, Italy
¹⁵ P.N. Lebedev Institute of Physics (FIAN), Russian Academy of Sciences, Moscow, Russia
¹⁶ Università “Federico II” e Sezione INFN, Napoli, Italy
¹⁷ Columbia University, New York, USA
¹⁸ Nuclear and Astrophysics Laboratory, University of Oxford, Oxford, UK
¹⁹ Università degli Studi e Sezione INFN, Padova, Italy
²⁰ LPNHE, Universités de Paris VI et VII, Paris, France
²¹ Università “La Sapienza” e Sezione INFN Roma I, Roma, Italy
²² Università degli Studi e Sezione INFN Roma III, Roma, Italy
²³ Dept. of Physics, University of Sheffield, Sheffield, UK
²⁴ Faculty of Physics, St. Kliment Ohridski University, Sofia, Bulgaria
²⁵ Institute for Nuclear Research and Nuclear Energy, Academy of Sciences, Sofia, Bulgaria
²⁶ Università degli Studi e Sezione INFN, Trieste, Italy
²⁷ Instituto de Física Corpuscular, IFIC, CSIC and Universidad de Valencia, Valencia, Spain
²⁸ FNAL, Batavia, Illinois, USA
²⁹ Codian Ltd., Langley, Slough, UK
³⁰ University of Glasgow, Glasgow, UK
³¹ Imperial College, University of London, London, UK
³² Instituto de Física de Cantabria, Univ. de Cantabria, Santander, Spain
³³ ITEP, Moscow, Russian Federation
³⁴ SpinX Technologies, Geneva, Switzerland
³⁵ TRIUMF, Vancouver, Canada
³⁶ University of St. Gallen, St. Gallen, Switzerland
³⁷ Ecoanalitica, Moscow State University, Moscow, Russia
³⁸ Çukurova University, Adana, Turkey
³⁹ III Phys. Inst. B, RWTH, Aachen, Germany
⁴⁰ INFN, Sezione di Ferrara, Ferrara, Italy
⁴¹ University of Rome Tor Vergata, Rome, Italy
⁴² LBL, Berkeley, California, USA
⁴³ Royal Holloway, University of London, London, UK
⁴⁴ University of Sussex, Brighton, UK
⁴⁵ ESA/ESTEC, Noordwijk, The Netherlands

^* e-mail: gomez@mail.cern.ch

Received: 13 February 2007
Revised: 27 May 2007
Published online: 1 August 2007

Abstract

A measurement of the double-differential cross-section for the production of charged pions in proton–tantalum collisions emitted at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a tantalum target with a thickness of 5% of a nuclear interaction length. The angular and momentum range covered by the experiment (100 MeV/c ≤p< 800 MeV/c and 0.35 rad ≤θ< 2.15 rad) is of particular importance for the design of a neutrino factory. The produced particles were detected using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. Track recognition, momentum determination and particle identification were all performed based on the measurements made with the TPC. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d²σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). In addition, the pion yields within the acceptance of typical neutrino factory designs are shown as a function of beam momentum. The measurement of these yields within a single experiment eliminates most systematic errors in the comparison between rates at different beam momenta and between positive and negative pion production.