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Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of $ \pi^{0}$ $ \pi^{\pm}$ pairs off protons and off neutrons

Oberle, M. ; Ahrens, J. ; Annand, J. ; Arends, H. ; Bantawa, K. ; Bartolome, P. ; Beck, R. ; Bekrenev, V. ; Berghäuser, H. ; Braghieri, A. ; Branford, D. ; Briscoe, W. ; Brudvik, J. ; Cherepnya, S. ; Demissie, B. ; Dieterle, M. ; Downie, E. ; Drexler, P. ; Fil'kov, L. ; Fix, A. ; Glazier, D. ; Heid, E. ; Hornidge, D. ; Howdle, D. ; Huber, G. ; Jahn, O. ; Jaegle, I. ; Jude, T. ; Käser, A. ; Kashevarov, V. ; Keshelashvili, I. ; Kondratiev, R. ; Korolija, M. ; Kruglov, S. ; Krusche, B. ; Kulbardis, A. ; Lisin, V. ; Livingston, K. ; MacGregor, I. ; Maghrbi, Y. ; Mancell, J. ; Manley, D. ; Marinides, Z. ; Martinez, M. ; McGeorge, J. ; McNicoll, E. ; Mekterovic, D. ; Metag, V. ; Micanovic, S. ; Middleton, D. ; Mushkarenkov, A. ; Nefkens, B. ; Nikolaev, A. ; Novotny, R. ; Ostrick, M. ; Oussena, B. ; Pedroni, P. ; Pheron, F. ; Polonski, A. ; Prakhov, S. ; Robinson, J. ; Rosner, G. ; Rostomyan, T. ; Schumann, S. ; Sikora, M. ; Sober, D. ; Starostin, A. ; Supek, I. ; Thiel, M. ; Thomas, A. ; Unverzagt, M. ; Watts, D. ; Werthmüller, D. ; Witthauer, L. ; Zehr, F.

In: The European Physical Journal A, 2014, vol. 50, no. 3, p. 1-18

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    Titre
    • Measurement of the beam-helicity asymmetry I⊙ in the photoproduction of $ \pi^{0}$ $ \pi^{\pm}$ pairs off protons and off neutrons
    Auteur
    • Oberle, M.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Ahrens, J.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Annand, J.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Arends, H.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Bantawa, K.. Kent State University, 44242, Kent, Ohio, USA
    • Bartolome, P.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Beck, R.. Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115, Bonn, Germany
    • Bekrenev, V.. Petersburg Nuclear Physics Institute, RU-188300, Gatchina, Russia
    • Berghäuser, H.. II. Physikalisches Institut, University of Giessen, D-35392, Giessen, Germany
    • Braghieri, A.. INFN, Sezione di Pavia, I-27100 Pavia, Pavia, Italy
    • Branford, D.. School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
    • Briscoe, W.. Center for Nuclear Studies, The George Washington University, 20052, Washington, DC, USA
    • Brudvik, J.. University of California Los Angeles, 90095-1547, Los Angeles, California, USA
    • Cherepnya, S.. Lebedev Physical Institute, RU-119991, Moscow, Russia
    • Demissie, B.. Center for Nuclear Studies, The George Washington University, 20052, Washington, DC, USA
    • Dieterle, M.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Downie, E.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Drexler, P.. II. Physikalisches Institut, University of Giessen, D-35392, Giessen, Germany
    • Fil'kov, L.. Lebedev Physical Institute, RU-119991, Moscow, Russia
    • Fix, A.. Laboratory of Mathematical Physics, Tomsk Polytechnic University, Tomsk, Russia
    • Glazier, D.. School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
    • Heid, E.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Hornidge, D.. Mount Allison University, Sackville, E4L1E6, New Brunswick, Canada
    • Howdle, D.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Huber, G.. University of Regina, S4S-0A2, Regina, SK, Canada
    • Jahn, O.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Jaegle, I.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Jude, T.. School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
    • Käser, A.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Kashevarov, V.. Lebedev Physical Institute, RU-119991, Moscow, Russia
    • Keshelashvili, I.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Kondratiev, R.. Institute for Nuclear Research, RU-125047, Moscow, Russia
    • Korolija, M.. Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
    • Kruglov, S.. Petersburg Nuclear Physics Institute, RU-188300, Gatchina, Russia
    • Krusche, B.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Kulbardis, A.. Petersburg Nuclear Physics Institute, RU-188300, Gatchina, Russia
    • Lisin, V.. Institute for Nuclear Research, RU-125047, Moscow, Russia
    • Livingston, K.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • MacGregor, I.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Maghrbi, Y.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Mancell, J.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Manley, D.. Kent State University, 44242, Kent, Ohio, USA
    • Marinides, Z.. Center for Nuclear Studies, The George Washington University, 20052, Washington, DC, USA
    • Martinez, M.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • McGeorge, J.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • McNicoll, E.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Mekterovic, D.. Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
    • Metag, V.. II. Physikalisches Institut, University of Giessen, D-35392, Giessen, Germany
    • Micanovic, S.. Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
    • Middleton, D.. Mount Allison University, Sackville, E4L1E6, New Brunswick, Canada
    • Mushkarenkov, A.. INFN, Sezione di Pavia, I-27100 Pavia, Pavia, Italy
    • Nefkens, B.. University of California Los Angeles, 90095-1547, Los Angeles, California, USA
    • Nikolaev, A.. Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115, Bonn, Germany
    • Novotny, R.. II. Physikalisches Institut, University of Giessen, D-35392, Giessen, Germany
    • Ostrick, M.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Oussena, B.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Pedroni, P.. INFN, Sezione di Pavia, I-27100 Pavia, Pavia, Italy
    • Pheron, F.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Polonski, A.. Institute for Nuclear Research, RU-125047, Moscow, Russia
    • Prakhov, S.. University of California Los Angeles, 90095-1547, Los Angeles, California, USA
    • Robinson, J.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Rosner, G.. School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
    • Rostomyan, T.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Schumann, S.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Sikora, M.. School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
    • Sober, D.. The Catholic University of America, 20064, Washington, DC, USA
    • Starostin, A.. University of California Los Angeles, 90095-1547, Los Angeles, California, USA
    • Supek, I.. Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
    • Thiel, M.. II. Physikalisches Institut, University of Giessen, D-35392, Giessen, Germany
    • Thomas, A.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Unverzagt, M.. Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
    • Watts, D.. School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
    • Werthmüller, D.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Witthauer, L.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    • Zehr, F.. Department of Physics, University of Basel, CH-4056, Basel, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • The European Physical Journal A, 2014, vol. 50, no. 3, p. 1-18. Springer Berlin Heidelberg
    Autre version électronique
    Classification
    • Technologie, Sciences de l'ingénieur
    Identifiant OAI-PMH
    • oai:doc.rero.ch:326495
    Summary
    Abstract.: Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions $ \gamma p\rightarrow n\pi^{0}\pi^{+}$ off free protons and $ \gamma d \rightarrow (p)p\pi^{0}\pi^{-}$ and $ \gamma d\rightarrow (n)n\pi^{0}\pi^{+}$ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from $ \pi^{0}$ mesons were detected in the $ 4\pi$ electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region.