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Mullen C, Gardner S, Glazier DI, Kay SJD, Livingston K, Strakovsky II, Workman RL, Abt S, Achenbach P, Afzal F, Ahmed Z, Akondi CS, Annand JRM, Bashkanov M, Beck R, Biroth M, Borisov NS, Braghieri A, Briscoe WJ, Cividini F, Collicott C, Costanza S, Denig A, Dieterle M, Downie EJ, Drexler P, Fegan S, Ferretti-Bondy MI, Ghosal D, Gorodnov I, Gradl W, Günther M, Gurevic G, Heijkenskjöld L, Hornidge D, Huber GM, Jermann N, Kaeser A, Korolija M, Kashevarov VL, Krusche B, Kulikov VV, Lazarev A, Lutterer S, MacGregor IJD, Manley DM, Martel PP, Martemianov MA, Meier C, Miskimen R, Mocanu M, Mornacchi E, Neganov A, Oberle M, Ostrick M, Otte P, Paudyal D, Pedroni P, Powell A, Prakhov SN, Reicherz G, Ron G, Rostomyan T, Sfienti C, Sokhoyan V, Spieker K, Steffen O, Strub T, Supek I, Thiel A, Thiel M, Thomas A, Unverzagt M, Usov YA, Wagner S, Walford NK, Watts DP, Werthmüller D, Wettig J, Witthauer L, Wolfes M, Zachariou N. Single π 0 production off neutrons bound in deuteron with linearly polarized photons. Eur Phys J A Hadron Nucl 2021; 57:205. [PMID: 34720708 PMCID: PMC8550430 DOI: 10.1140/epja/s10050-021-00521-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
The quasifree γ → d → π 0 n ( p ) photon beam asymmetry, Σ , has been measured at photon energies, E γ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 ∘ to 148 ∘ . In this kinematic region, polarization observables are sensitive to contributions from the Δ ( 1232 ) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new Σ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict π 0 n photoproduction observables, based on fits to published data in the channels π 0 p , π + n and π - p .
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Affiliation(s)
- C. Mullen
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - S. Gardner
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - D. I. Glazier
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - S. J. D. Kay
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD UK
- Department of Physics, University of Regina, Regina, SK S4S 0A2 Canada
| | - K. Livingston
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - I. I. Strakovsky
- Department of Physics, Institute for Nuclear Studies, The George Washington University, Washington, DC, 20052 USA
| | - R. L. Workman
- Department of Physics, Institute for Nuclear Studies, The George Washington University, Washington, DC, 20052 USA
| | - S. Abt
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - P. Achenbach
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - F. Afzal
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany
| | - Z. Ahmed
- Department of Physics, University of Regina, Regina, SK S4S 0A2 Canada
| | | | - J. R. M. Annand
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - M. Bashkanov
- Department of Physics, University of York, Heslington, York, Y010 5DD UK
| | - R. Beck
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany
| | - M. Biroth
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | | | | | - W. J. Briscoe
- Department of Physics, Institute for Nuclear Studies, The George Washington University, Washington, DC, 20052 USA
| | - F. Cividini
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - C. Collicott
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | | | - A. Denig
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - M. Dieterle
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - E. J. Downie
- Department of Physics, Institute for Nuclear Studies, The George Washington University, Washington, DC, 20052 USA
| | - P. Drexler
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - S. Fegan
- Department of Physics, University of York, Heslington, York, Y010 5DD UK
| | - M. I. Ferretti-Bondy
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - D. Ghosal
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | | | - W. Gradl
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - M. Günther
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - G. Gurevic
- Institute for Nuclear Research, 125047 Moscow, Russia
| | - L. Heijkenskjöld
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - D. Hornidge
- Mount Allison University, Sackville, NB E4L3B5 Canada
| | - G. M. Huber
- Department of Physics, University of Regina, Regina, SK S4S 0A2 Canada
| | - N. Jermann
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - A. Kaeser
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - M. Korolija
- Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - V. L. Kashevarov
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
- JINR, 141980 Dubna, Russia
| | - B. Krusche
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - V. V. Kulikov
- NRC “Kurchatov Institute”-ITEP, 117218 Moscow, Russia
| | - A. Lazarev
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany
| | - S. Lutterer
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - I. J. D. MacGregor
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | | | - P. P. Martel
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | | | - C. Meier
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - R. Miskimen
- University of Massachusetts, Amherst, MA 01003 USA
| | - M. Mocanu
- Department of Physics, University of York, Heslington, York, Y010 5DD UK
| | - E. Mornacchi
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | | | - M. Oberle
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - M. Ostrick
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - P. Otte
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - D. Paudyal
- Department of Physics, University of Regina, Regina, SK S4S 0A2 Canada
| | - P. Pedroni
- INFN Sezione di Pavia, 27100 Pavia, Italy
| | - A. Powell
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - S. N. Prakhov
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - G. Reicherz
- Institut für Experimentalphysik, Ruhr-University of Bochum, 44801 Bochum, Germany
| | - G. Ron
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, Israel
| | - T. Rostomyan
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - C. Sfienti
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - V. Sokhoyan
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - K. Spieker
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany
| | - O. Steffen
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Th. Strub
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - I. Supek
- Rudjer Boskovic Institute, 10000 Zagreb, Croatia
| | - A. Thiel
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, 53115 Bonn, Germany
| | - M. Thiel
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - A. Thomas
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - M. Unverzagt
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | | | - S. Wagner
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - N. K. Walford
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - D. P. Watts
- Department of Physics, University of York, Heslington, York, Y010 5DD UK
| | - D. Werthmüller
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK
| | - J. Wettig
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - L. Witthauer
- Institut für Physik, University of Basel, 4056 Basel, Switzerland
| | - M. Wolfes
- Institut für Kernphysik, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - N. Zachariou
- Department of Physics, University of York, Heslington, York, Y010 5DD UK
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2
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Dieterle M, Witthauer L, Fix A, Abt S, Achenbach P, Adlarson P, Afzal F, Aguar Bartolome P, Ahmed Z, Annand JRM, Arends HJ, Bashkanov M, Beck R, Biroth M, Borisov N, Braghieri A, Briscoe WJ, Cividini F, Collicott C, Costanza S, Denig A, Dolzhikov AS, Downie EJ, Drexler P, Gardner S, Ghosal D, Glazier DI, Gorodnov I, Gradl W, Günther M, Gurevich D, Heijkenskjöld L, Hornidge D, Huber GM, Käser A, Kashevarov VL, Kay S, Keshelashvili I, Kondratiev R, Korolija M, Krusche B, Lazarev A, Lisin V, Livingston K, Lutterer S, MacGregor IJD, Manley DM, Martel PP, Metag V, Meyer W, Middleton DG, Miskimen R, Mornacchi E, Mullen C, Mushkarenkov A, Neganov A, Neiser A, Oberle M, Ostrick M, Otte PB, Paudyal D, Pedroni P, Polonski A, Powell A, Prakhov SN, Reicherz G, Ron G, Rostomyan T, Sarty A, Sfienti C, Sokhoyan V, Spieker K, Steffen O, Strakovsky II, Strub T, Supek I, Thiel A, Thiel M, Thomas A, Unverzagt M, Usov YA, Wagner S, Walford NK, Watts DP, Werthmüller D, Wettig J, Wolfes M, Zana LA. Helicity-Dependent Cross Sections for the Photoproduction of π^{0} Pairs from Nucleons. Phys Rev Lett 2020; 125:062001. [PMID: 32845675 DOI: 10.1103/physrevlett.125.062001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/17/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
The double-polarization observable E and helicity-dependent cross sections σ_{1/2}, σ_{3/2} have been measured for the photoproduction of π^{0} pairs off quasifree protons and neutrons at the Mainz MAMI accelerator with the Crystal Ball/TAPS setup. A circularly polarized photon beam was produced by bremsstrahlung from longitudinally polarized electrons and impinged on a longitudinally polarized deuterated butanol target. The reaction products were detected with an almost 4π covering calorimeter. The results reveal for the first time the helicity- and isospin-dependent structure of the γN→Nπ^{0}π^{0} reaction. They are compared to predictions from reaction models in view of nucleon resonance contributions and also to a refit of one model that predicted results for the proton and for the neutron target. The comparison of the prediction and the refit demonstrates the large impact of the new data.
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Affiliation(s)
- M Dieterle
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - L Witthauer
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - A Fix
- Laboratory of Mathematical Physics, Tomsk Polytechnic University, 634034 Tomsk, Russia
| | - S Abt
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - P Achenbach
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - P Adlarson
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - F Afzal
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - P Aguar Bartolome
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - Z Ahmed
- University of Regina, Regina, Saskatchewan S4S-0A2 Canada
| | - J R M Annand
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Bashkanov
- SUPA School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - R Beck
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - M Biroth
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N Borisov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - A Braghieri
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
| | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - F Cividini
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - C Collicott
- Department of Astronomy and Physics, Saint Mary's University, E4L1E6 Halifax, Canada
| | - S Costanza
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
| | - A Denig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - A S Dolzhikov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - E J Downie
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - P Drexler
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- II. Physikalisches Institut, University of Giessen, D-35392 Giessen, Germany
| | - S Gardner
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - D Ghosal
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - D I Glazier
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
- SUPA School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - I Gorodnov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - W Gradl
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Günther
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - D Gurevich
- Institute for Nuclear Research, RU-125047 Moscow, Russia
| | - L Heijkenskjöld
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L1E6, Canada
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S-0A2 Canada
| | - A Käser
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - V L Kashevarov
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - S Kay
- SUPA School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - I Keshelashvili
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - R Kondratiev
- Institute for Nuclear Research, RU-125047 Moscow, Russia
| | - M Korolija
- Rudjer Boskovic Institute, HR-10000 Zagreb, Croatia
| | - B Krusche
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - A Lazarev
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - V Lisin
- Institute for Nuclear Research, RU-125047 Moscow, Russia
| | - K Livingston
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - S Lutterer
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - I J D MacGregor
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - D M Manley
- Kent State University, Kent, Ohio 44242, USA
| | - P P Martel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Mount Allison University, Sackville, New Brunswick E4L3B5, Canada
| | - V Metag
- II. Physikalisches Institut, University of Giessen, D-35392 Giessen, Germany
| | - W Meyer
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
| | - D G Middleton
- Mount Allison University, Sackville, New Brunswick E4L3B5, Canada
| | - R Miskimen
- University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - E Mornacchi
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - C Mullen
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - A Mushkarenkov
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
- University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - A Neganov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - A Neiser
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Oberle
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - M Ostrick
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - P B Otte
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - D Paudyal
- University of Regina, Regina, Saskatchewan S4S-0A2 Canada
| | - P Pedroni
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
| | - A Polonski
- Institute for Nuclear Research, RU-125047 Moscow, Russia
| | - A Powell
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - S N Prakhov
- University of California Los Angeles, Los Angeles, California 90095-1547, USA
| | - G Reicherz
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
| | - G Ron
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - T Rostomyan
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - A Sarty
- Department of Astronomy and Physics, Saint Mary's University, E4L1E6 Halifax, Canada
| | - C Sfienti
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - V Sokhoyan
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - K Spieker
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - O Steffen
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - I I Strakovsky
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - T Strub
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - I Supek
- Rudjer Boskovic Institute, HR-10000 Zagreb, Croatia
| | - A Thiel
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - M Thiel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - A Thomas
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - Yu A Usov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - S Wagner
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N K Walford
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - D P Watts
- SUPA School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D Werthmüller
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - J Wettig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Wolfes
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - L A Zana
- SUPA School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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3
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Bashkanov M, Watts DP, Kay SJD, Abt S, Achenbach P, Adlarson P, Afzal F, Ahmed Z, Akondi CS, Annand JRM, Arends HJ, Beck R, Biroth M, Borisov N, Braghieri A, Briscoe WJ, Cividini F, Collicott C, Costanza S, Denig A, Downie EJ, Drexler P, Fegan S, Fix A, Gardner S, Ghosal D, Glazier DI, Gorodnov I, Gradl W, Günther M, Gurevich D, Heijkenskjöld L, Hornidge D, Huber GM, Käser A, Kashevarov VL, Korolija M, Krusche B, Lazarev A, Livingston K, Lutterer S, MacGregor IJD, Manley DM, Martel PP, Miskimen R, Mornacchi E, Mullen C, Neganov A, Neiser A, Ostrick M, Otte PB, Paudyal D, Pedroni P, Powell A, Prakhov SN, Ron G, Sarty A, Sfienti C, Sokhoyan V, Spieker K, Steffen O, Strakovsky II, Strub T, Supek I, Thiel A, Thiel M, Thomas A, Usov YA, Wagner S, Walford NK, Werthmüller D, Wettig J, Wolfes M, Zachariou N, Zana LA. Signatures of the d^{*}(2380) Hexaquark in d(γ,pn[over →]). Phys Rev Lett 2020; 124:132001. [PMID: 32302204 DOI: 10.1103/physrevlett.124.132001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/30/2020] [Accepted: 03/02/2020] [Indexed: 06/11/2023]
Abstract
We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570 MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom. A Legendre polynomial decomposition suggests this behavior could be related to the excitation of the d^{*}(2380) hexaquark.
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Affiliation(s)
- M Bashkanov
- Department of Physics, University of York, Heslington, York Y010 5DD, United Kingdom
| | - D P Watts
- Department of Physics, University of York, Heslington, York Y010 5DD, United Kingdom
| | - S J D Kay
- University of Regina, Regina, SK S4S0A2 Canada
| | - S Abt
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - P Achenbach
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - P Adlarson
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - F Afzal
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - Z Ahmed
- University of Regina, Regina, SK S4S0A2 Canada
| | - C S Akondi
- Kent State University, Kent, Ohio 44242, USA
| | - J R M Annand
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - R Beck
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - M Biroth
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N Borisov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - A Braghieri
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
| | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - F Cividini
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - C Collicott
- Department of Astronomy and Physics, Saint Mary's University, E4L1E6 Halifax, Canada
| | - S Costanza
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
- Dipartimento di Fisica, Università di Pavia, I-27100 Pavia, Italy
| | - A Denig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - E J Downie
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - P Drexler
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- II. Physikalisches Institut, University of Giessen, D-35392 Giessen, Germany
| | - S Fegan
- Department of Physics, University of York, Heslington, York Y010 5DD, United Kingdom
| | - A Fix
- Tomsk Polytechnic University, 634034 Tomsk, Russia
| | - S Gardner
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D Ghosal
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - D I Glazier
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - I Gorodnov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - W Gradl
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Günther
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - D Gurevich
- Institute for Nuclear Research, RU-125047 Moscow, Russia
| | - L Heijkenskjöld
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L1E6, Canada
| | - G M Huber
- University of Regina, Regina, SK S4S0A2 Canada
| | - A Käser
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - V L Kashevarov
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - M Korolija
- Rudjer Boskovic Institute, HR-10000 Zagreb, Croatia
| | - B Krusche
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - A Lazarev
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - K Livingston
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S Lutterer
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - I J D MacGregor
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D M Manley
- Kent State University, Kent, Ohio 44242, USA
| | - P P Martel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Mount Allison University, Sackville, New Brunswick E4L1E6, Canada
| | - R Miskimen
- University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - E Mornacchi
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - C Mullen
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - A Neganov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - A Neiser
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Ostrick
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - P B Otte
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - D Paudyal
- University of Regina, Regina, SK S4S0A2 Canada
| | - P Pedroni
- INFN Sezione di Pavia, I-27100 Pavia, Pavia, Italy
| | - A Powell
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S N Prakhov
- University of California Los Angeles, Los Angeles, California 90095-1547, USA
| | - G Ron
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - A Sarty
- Department of Astronomy and Physics, Saint Mary's University, E4L1E6 Halifax, Canada
| | - C Sfienti
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - V Sokhoyan
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - K Spieker
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - O Steffen
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - I I Strakovsky
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052, USA
| | - T Strub
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - I Supek
- Rudjer Boskovic Institute, HR-10000 Zagreb, Croatia
| | - A Thiel
- Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, D-53115 Bonn, Germany
| | - M Thiel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - A Thomas
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - Yu A Usov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - S Wagner
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N K Walford
- Department of Physics, University of Basel, Ch-4056 Basel, Switzerland
| | - D Werthmüller
- Department of Physics, University of York, Heslington, York Y010 5DD, United Kingdom
| | - J Wettig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Wolfes
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N Zachariou
- Department of Physics, University of York, Heslington, York Y010 5DD, United Kingdom
| | - L A Zana
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
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4
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Witthauer L, Dieterle M, Abt S, Achenbach P, Afzal F, Ahmed Z, Annand JRM, Arends HJ, Bashkanov M, Beck R, Biroth M, Borisov NS, Braghieri A, Briscoe WJ, Cividini F, Costanza S, Collicott C, Denig A, Downie EJ, Drexler P, Ferretti-Bondy MI, Gardner S, Garni S, Glazier DI, Glowa D, Gradl W, Günther M, Gurevich GM, Hamilton D, Hornidge D, Huber GM, Käser A, Kashevarov VL, Kay S, Keshelashvili I, Kondratiev R, Korolija M, Krusche B, Lazarev AB, Linturi JM, Lisin V, Livingston K, Lutterer S, MacGregor IJD, Mancell J, Manley DM, Martel PP, Metag V, Meyer W, Miskimen R, Mornacchi E, Mushkarenkov A, Neganov AB, Neiser A, Oberle M, Ostrick M, Otte PB, Paudyal D, Pedroni P, Polonski A, Prakhov SN, Rajabi A, Reicherz G, Ron G, Rostomyan T, Sarty A, Sfienti C, Sikora MH, Sokhoyan V, Spieker K, Steffen O, Strakovski II, Strub T, Supek I, Thiel A, Thiel M, Thomas A, Unverzagt M, Usov YA, Wagner S, Walford NK, Watts DP, Werthmüller D, Wettig J, Wolfes M, Zana L. Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections. Phys Rev Lett 2016; 117:132502. [PMID: 27715117 DOI: 10.1103/physrevlett.117.132502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Indexed: 06/06/2023]
Abstract
The double polarization observable E and the helicity dependent cross sections σ_{1/2} and σ_{3/2} were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The almost 4π detector setup of the Crystal Ball and TAPS is ideally suited to detect the recoil nucleons and the decay photons from η→2γ and η→3π^{0}. The results show that the narrow structure previously observed in η photoproduction from the neutron is only apparent in σ_{1/2} and hence, most likely related to a spin-1/2 amplitude. Nucleon resonances that contribute to this partial wave in η production are only N 1/2^{-} (S_{11}) and N 1/2^{+} (P_{11}). Furthermore, the extracted Legendre coefficients of the angular distributions for σ_{1/2} are in good agreement with recent reaction model predictions assuming a narrow resonance in the P_{11} wave as the origin of this structure.
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Affiliation(s)
- L Witthauer
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - M Dieterle
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - S Abt
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - P Achenbach
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - F Afzal
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany
| | - Z Ahmed
- University of Regina, Regina, SK S4S 0A2 Canada
| | - J R M Annand
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Bashkanov
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - R Beck
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany
| | - M Biroth
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N S Borisov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | | | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA
| | - F Cividini
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - S Costanza
- INFN Sezione di Pavia, I-27100 Pavia, Italy
| | - C Collicott
- Department of Astronomy and Physics, Saint Marys University, Halifax, Nova Scotia B3H 3C3, Canada
| | - A Denig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - E J Downie
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA
| | - P Drexler
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | | | - S Gardner
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S Garni
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - D I Glazier
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - D Glowa
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - W Gradl
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Günther
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - G M Gurevich
- Institute for Nuclear Research, 125047 Moscow, Russia
| | - D Hamilton
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | - G M Huber
- University of Regina, Regina, SK S4S 0A2 Canada
| | - A Käser
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - V L Kashevarov
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - S Kay
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - I Keshelashvili
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - R Kondratiev
- Institute for Nuclear Research, 125047 Moscow, Russia
| | - M Korolija
- Rudjer Boskovic Institute, HR 10000 Zagreb, Croatia
| | - B Krusche
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - A B Lazarev
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - J M Linturi
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - V Lisin
- Institute for Nuclear Research, 125047 Moscow, Russia
| | - K Livingston
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S Lutterer
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - I J D MacGregor
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - J Mancell
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D M Manley
- Kent State University, Kent, Ohio 44242-0001, USA
| | - P P Martel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - V Metag
- II. Physikalisches Institut, University of Giessen, D-35392 Giessen, Germany
| | - W Meyer
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
| | - R Miskimen
- University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - E Mornacchi
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - A Mushkarenkov
- Institute for Nuclear Research, 125047 Moscow, Russia
- University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - A B Neganov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - A Neiser
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Oberle
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - M Ostrick
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - P B Otte
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - D Paudyal
- University of Regina, Regina, SK S4S 0A2 Canada
| | - P Pedroni
- INFN Sezione di Pavia, I-27100 Pavia, Italy
| | - A Polonski
- Institute for Nuclear Research, 125047 Moscow, Russia
| | - S N Prakhov
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- University of California at Los Angeles, Los Angeles, California 90095-1547, USA
| | - A Rajabi
- University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
| | - G Reicherz
- Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany
| | - G Ron
- Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - T Rostomyan
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - A Sarty
- Department of Astronomy and Physics, Saint Marys University, Halifax, Nova Scotia B3H 3C3, Canada
| | - C Sfienti
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M H Sikora
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - V Sokhoyan
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA
| | - K Spieker
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany
| | - O Steffen
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - I I Strakovski
- Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA
| | - Th Strub
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - I Supek
- Rudjer Boskovic Institute, HR 10000 Zagreb, Croatia
| | - A Thiel
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany
| | - M Thiel
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - A Thomas
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - Yu A Usov
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - S Wagner
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - N K Walford
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - D P Watts
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
| | - D Werthmüller
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - J Wettig
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - M Wolfes
- Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany
| | - L Zana
- SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom
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5
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Tarbert CM, Watts DP, Glazier DI, Aguar P, Ahrens J, Annand JRM, Arends HJ, Beck R, Bekrenev V, Boillat B, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Codling R, Downie EJ, Foehl K, Grabmayr P, Gregor R, Heid E, Hornidge D, Jahn O, Kashevarov VL, Knezevic A, Kondratiev R, Korolija M, Kotulla M, Krambrich D, Krusche B, Lang M, Lisin V, Livingston K, Lugert S, MacGregor IJD, Manley DM, Martinez M, McGeorge JC, Mekterovic D, Metag V, Nefkens BMK, Nikolaev A, Novotny R, Owens RO, Pedroni P, Polonski A, Prakhov SN, Price JW, Rosner G, Rost M, Rostomyan T, Schadmand S, Schumann S, Sober D, Starostin A, Supek I, Thomas A, Unverzagt M, Walcher T, Zana L, Zehr F. Neutron skin of (208)pb from coherent pion photoproduction. Phys Rev Lett 2014; 112:242502. [PMID: 24996085 DOI: 10.1103/physrevlett.112.242502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Indexed: 06/03/2023]
Abstract
Information on the size and shape of the neutron skin on (208)Pb is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be c(n)=6.70±0.03(stat.) fm and a(n)=0.55±0.01(stat.)(-0.03)(+0.02)(sys.) fm, respectively, corresponding to a neutron skin thickness Δr(np)=0.15±0.03(stat.)(-0.03)(+0.01)(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of (208)Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.
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Affiliation(s)
- C M Tarbert
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D P Watts
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D I Glazier
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - P Aguar
- Institut für Kernphysik, University of Mainz, Germany
| | - J Ahrens
- Institut für Kernphysik, University of Mainz, Germany
| | - J R M Annand
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, Germany
| | - R Beck
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - V Bekrenev
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - B Boillat
- Institut für Physik, University of Basel, Basel, Switzerland
| | | | - D Branford
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, D.C. 20052, USA
| | - J Brudvik
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | | | - R Codling
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - E J Downie
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - K Foehl
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - P Grabmayr
- Physikalisches Institut Universität Tübingen, Tübingen, Germany
| | - R Gregor
- II. Physikalisches Institut, University of Giessen, Germany
| | - E Heid
- Institut für Kernphysik, University of Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | - O Jahn
- Institut für Kernphysik, University of Mainz, Germany
| | | | - A Knezevic
- Rudjer Boskovic Institute, Zagreb, Croatia
| | | | - M Korolija
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - M Kotulla
- Institut für Physik, University of Basel, Basel, Switzerland
| | - D Krambrich
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - B Krusche
- Institut für Physik, University of Basel, Basel, Switzerland
| | - M Lang
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - V Lisin
- Institute for Nuclear Research, Moscow, Russia
| | - K Livingston
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - S Lugert
- II. Physikalisches Institut, University of Giessen, Germany
| | - I J D MacGregor
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - D M Manley
- Kent State University, Kent, Ohio 44240, USA
| | - M Martinez
- Institut für Kernphysik, University of Mainz, Germany
| | - J C McGeorge
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - V Metag
- II. Physikalisches Institut, University of Giessen, Germany
| | - B M K Nefkens
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - A Nikolaev
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - R Novotny
- II. Physikalisches Institut, University of Giessen, Germany
| | - R O Owens
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - A Polonski
- Institute for Nuclear Research, Moscow, Russia
| | - S N Prakhov
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - J W Price
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - G Rosner
- SUPA, Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - M Rost
- Institut für Kernphysik, University of Mainz, Germany
| | | | - S Schadmand
- II. Physikalisches Institut, University of Giessen, Germany
| | - S Schumann
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - D Sober
- The Catholic University of America, Washington, D.C. 20064, USA
| | - A Starostin
- University of California at Los Angeles, Los Angeles, California 90095, USA
| | - I Supek
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - A Thomas
- Institut für Kernphysik, University of Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University Bonn, Germany
| | - Th Walcher
- Institut für Kernphysik, University of Mainz, Germany
| | - L Zana
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - F Zehr
- Institut für Physik, University of Basel, Basel, Switzerland
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6
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Dieterle M, Keshelashvili I, Ahrens J, Annand JRM, Arends HJ, Bantawa K, Bartolome PA, Beck R, Bekrenev V, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Demissie B, Downie EJ, Drexler P, Fil'kov LV, Fix A, Glazier DI, Hamilton D, Heid E, Hornidge D, Howdle D, Huber GM, Jaegle I, Jahn O, Jude TC, Käser A, Kashevarov VL, Kondratiev R, Korolija M, Kruglov SP, Krusche B, Kulbardis A, Lisin V, Livingston K, MacGregor IJD, Maghrbi Y, Mancell J, Manley DM, Marinides Z, Martinez M, McGeorge JC, McNicoll E, Mekterovic D, Metag V, Micanovic S, Middleton DG, Mushkarenkov A, Nefkens BMK, Nikolaev A, Novotny R, Oberle M, Ostrick M, Oussena B, Pedroni P, Pheron F, Polonski A, Prakhov SN, Robinson J, Rosner G, Rostomyan T, Schumann S, Sikora MH, Sober D, Starostin A, Supek I, Thiel M, Thomas A, Unverzagt M, Watts DP, Werthmüller D, Witthauer L. Photoproduction of π0 mesons off neutrons in the nucleon resonance region. Phys Rev Lett 2014; 112:142001. [PMID: 24765945 DOI: 10.1103/physrevlett.112.142001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Indexed: 06/03/2023]
Abstract
Precise angular distributions have been measured for the first time for the photoproduction of π0 mesons off neutrons bound in the deuteron. The effects from nuclear Fermi motion have been eliminated by a complete kinematic reconstruction of the final state. The influence of final-state-interaction effects has been estimated by a comparison of the reaction cross section for quasifree protons bound in the deuteron to the results for free protons and then applied as a correction to the quasifree neutron data. The experiment was performed at the tagged photon facility of the Mainz Microtron MAMI with the Crystal Ball and TAPS detector setup for incident photon energies between 0.45 and 1.4 GeV. The results are compared to the predictions from reaction models and partial-wave analyses based on data from other isospin channels. The model predictions show large discrepancies among each other and the present data will provide much tighter constraints. This is demonstrated by the results of a new analysis in the framework of the Bonn-Gatchina coupled-channel analysis which included the present data.
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Affiliation(s)
- M Dieterle
- Department of Physics, University of Basel, Switzerland
| | | | - J Ahrens
- Institut für Kernphysik, University of Mainz, Germany
| | - J R M Annand
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - H J Arends
- Institut für Kernphysik, University of Mainz, Germany
| | - K Bantawa
- Kent State University, Kent, Ohio, USA
| | - P A Bartolome
- Institut für Kernphysik, University of Mainz, Germany
| | - R Beck
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Germany
| | - V Bekrenev
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | | | - D Branford
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
| | - W J Briscoe
- Center for Nuclear Studies, The George Washington University, Washington, DC, USA
| | - J Brudvik
- University of California at Los Angeles, Los Angeles, California, USA
| | | | - B Demissie
- Center for Nuclear Studies, The George Washington University, Washington, DC, USA
| | - E J Downie
- Institut für Kernphysik, University of Mainz, Germany and Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom and Center for Nuclear Studies, The George Washington University, Washington, DC, USA
| | - P Drexler
- II. Physikalisches Institut, University of Giessen, Germany
| | | | - A Fix
- Laboratory of Mathematical Physics, Tomsk Polytechnic University, Tomsk, Russia
| | - D I Glazier
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
| | - D Hamilton
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - E Heid
- Institut für Kernphysik, University of Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | - D Howdle
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2 Canada
| | - I Jaegle
- Department of Physics, University of Basel, Switzerland
| | - O Jahn
- Institut für Kernphysik, University of Mainz, Germany
| | - T C Jude
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
| | - A Käser
- Department of Physics, University of Basel, Switzerland
| | - V L Kashevarov
- Institut für Kernphysik, University of Mainz, Germany and Lebedev Physical Institute, Moscow, Russia
| | | | - M Korolija
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - S P Kruglov
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - B Krusche
- Department of Physics, University of Basel, Switzerland
| | - A Kulbardis
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - V Lisin
- Institute for Nuclear Research, Moscow, Russia
| | - K Livingston
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - I J D MacGregor
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - Y Maghrbi
- Department of Physics, University of Basel, Switzerland
| | - J Mancell
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | | | - Z Marinides
- Center for Nuclear Studies, The George Washington University, Washington, DC, USA
| | - M Martinez
- Institut für Kernphysik, University of Mainz, Germany
| | - J C McGeorge
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - E McNicoll
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | | | - V Metag
- II. Physikalisches Institut, University of Giessen, Germany
| | | | - D G Middleton
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | | | - B M K Nefkens
- University of California at Los Angeles, Los Angeles, California, USA
| | - A Nikolaev
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Germany
| | - R Novotny
- II. Physikalisches Institut, University of Giessen, Germany
| | - M Oberle
- Department of Physics, University of Basel, Switzerland
| | - M Ostrick
- Institut für Kernphysik, University of Mainz, Germany
| | - B Oussena
- Institut für Kernphysik, University of Mainz, Germany and Center for Nuclear Studies, The George Washington University, Washington, DC, USA
| | | | - F Pheron
- Department of Physics, University of Basel, Switzerland
| | - A Polonski
- Institute for Nuclear Research, Moscow, Russia
| | - S N Prakhov
- University of California at Los Angeles, Los Angeles, California, USA
| | - J Robinson
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - G Rosner
- Department of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
| | - T Rostomyan
- Department of Physics, University of Basel, Switzerland
| | - S Schumann
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Germany
| | - M H Sikora
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
| | - D Sober
- The Catholic University of America, Washington, DC, USA
| | - A Starostin
- University of California at Los Angeles, Los Angeles, California, USA
| | - I Supek
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - M Thiel
- Institut für Kernphysik, University of Mainz, Germany and II. Physikalisches Institut, University of Giessen, Germany
| | - A Thomas
- Institut für Kernphysik, University of Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, University of Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Germany
| | - D P Watts
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
| | - D Werthmüller
- Department of Physics, University of Basel, Switzerland
| | - L Witthauer
- Department of Physics, University of Basel, Switzerland
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7
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Werthmüller D, Witthauer L, Keshelashvili I, Aguar-Bartolomé P, Ahrens J, Annand JRM, Arends HJ, Bantawa K, Beck R, Bekrenev V, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Demissie B, Dieterle M, Downie EJ, Drexler P, Fil'kov LV, Fix A, Glazier DI, Hamilton D, Heid E, Hornidge D, Howdle D, Huber GM, Jaegle I, Jahn O, Jude TC, Käser A, Kashevarov VL, Kondratiev R, Korolija M, Kruglov SP, Krusche B, Kulbardis A, Lisin V, Livingston K, MacGregor IJD, Maghrbi Y, Mancell J, Manley DM, Marinides Z, Martinez M, McGeorge JC, McNicoll EF, Metag V, Middleton DG, Mushkarenkov A, Nefkens BMK, Nikolaev A, Novotny R, Oberle M, Ostrick M, Oussena B, Pedroni P, Pheron F, Polonski A, Prakhov SN, Robinson J, Rosner G, Rostomyan T, Schumann S, Sikora MH, Sober D, Starostin A, Supek I, Thiel M, Thomas A, Unverzagt M, Watts DP. Narrow structure in the excitation function of η photoproduction off the neutron. Phys Rev Lett 2013; 111:232001. [PMID: 24476257 DOI: 10.1103/physrevlett.111.232001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 10/28/2013] [Indexed: 06/03/2023]
Abstract
The photoproduction of η mesons off nucleons bound in 2H and 3He has been measured in coincidence with recoil protons and recoil neutrons for incident photon energies from threshold up to 1.4 GeV. The experiments were performed at the Mainz MAMI accelerator, using the Glasgow tagged photon facility. Decay photons from the η→2γ and η→3π0 decays and the recoil nucleons were detected with an almost 4π electromagnetic calorimeter combining the Crystal Ball and TAPS detectors. The data from both targets are of excellent statistical quality and show a narrow structure in the excitation function of γn→nη. The results from the two measurements are consistent, taking into account the expected effects from nuclear Fermi motion. The best estimates for position and intrinsic width of the structure are W=(1670±5) MeV and Γ=(30±15) MeV. For the first time precise results for the angular dependence of this structure have been extracted.
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Affiliation(s)
- D Werthmüller
- Departement für Physik, Universität Basel, Switzerland
| | - L Witthauer
- Departement für Physik, Universität Basel, Switzerland
| | | | | | - J Ahrens
- Institut für Kernphysik, Universität Mainz, Germany
| | - J R M Annand
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - H J Arends
- Institut für Kernphysik, Universität Mainz, Germany
| | - K Bantawa
- Kent State University, Kent, Ohio, USA
| | - R Beck
- Institut für Kernphysik, Universität Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany
| | - V Bekrenev
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | | | - D Branford
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - W J Briscoe
- Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA
| | - J Brudvik
- University of California at Los Angeles, Los Angeles, California, USA
| | | | - B Demissie
- Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA
| | - M Dieterle
- Departement für Physik, Universität Basel, Switzerland
| | - E J Downie
- Institut für Kernphysik, Universität Mainz, Germany and SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom and Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA
| | - P Drexler
- II. Physikalisches Institut, Universität Giessen, Germany
| | | | - A Fix
- Laboratory of Mathematical Physics, Tomsk Polytechnic University, Tomsk, Russia
| | - D I Glazier
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D Hamilton
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - E Heid
- Institut für Kernphysik, Universität Mainz, Germany
| | - D Hornidge
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | - D Howdle
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - G M Huber
- University of Regina, Regina, SK S4S 0A2, Canada
| | - I Jaegle
- Departement für Physik, Universität Basel, Switzerland
| | - O Jahn
- Institut für Kernphysik, Universität Mainz, Germany
| | - T C Jude
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - A Käser
- Departement für Physik, Universität Basel, Switzerland
| | - V L Kashevarov
- Institut für Kernphysik, Universität Mainz, Germany and Lebedev Physical Institute, Moscow, Russia
| | | | - M Korolija
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - S P Kruglov
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - B Krusche
- Departement für Physik, Universität Basel, Switzerland
| | - A Kulbardis
- Petersburg Nuclear Physics Institute, Gatchina, Russia
| | - V Lisin
- Institute for Nuclear Research, Moscow, Russia
| | - K Livingston
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - I J D MacGregor
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Y Maghrbi
- Departement für Physik, Universität Basel, Switzerland
| | - J Mancell
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | | | - Z Marinides
- Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA
| | - M Martinez
- Institut für Kernphysik, Universität Mainz, Germany
| | - J C McGeorge
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - E F McNicoll
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - V Metag
- II. Physikalisches Institut, Universität Giessen, Germany
| | - D G Middleton
- Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada
| | | | - B M K Nefkens
- University of California at Los Angeles, Los Angeles, California, USA
| | - A Nikolaev
- Institut für Kernphysik, Universität Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany
| | - R Novotny
- II. Physikalisches Institut, Universität Giessen, Germany
| | - M Oberle
- Departement für Physik, Universität Basel, Switzerland
| | - M Ostrick
- Institut für Kernphysik, Universität Mainz, Germany
| | - B Oussena
- Institut für Kernphysik, Universität Mainz, Germany and Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA
| | | | - F Pheron
- Departement für Physik, Universität Basel, Switzerland
| | - A Polonski
- Institute for Nuclear Research, Moscow, Russia
| | - S N Prakhov
- Institut für Kernphysik, Universität Mainz, Germany and Institute for Nuclear Studies, The George Washington University, Washington, District of Columbia, USA and University of California at Los Angeles, Los Angeles, California, USA
| | - J Robinson
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - G Rosner
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - T Rostomyan
- Departement für Physik, Universität Basel, Switzerland
| | - S Schumann
- Institut für Kernphysik, Universität Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany
| | - M H Sikora
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - D Sober
- The Catholic University of America, Washington, District of Columbia, USA
| | - A Starostin
- University of California at Los Angeles, Los Angeles, California, USA
| | - I Supek
- Rudjer Boskovic Institute, Zagreb, Croatia
| | - M Thiel
- Institut für Kernphysik, Universität Mainz, Germany and II. Physikalisches Institut, Universität Giessen, Germany
| | - A Thomas
- Institut für Kernphysik, Universität Mainz, Germany
| | - M Unverzagt
- Institut für Kernphysik, Universität Mainz, Germany and Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany
| | - D P Watts
- SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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8
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Krambrich D, Zehr F, Fix A, Roca L, Aguar P, Ahrens J, Annand JRM, Arends HJ, Beck R, Bekrenev V, Boillat B, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Codling R, Downie EJ, Dexler P, Glazier DI, Grabmayr P, Gregor R, Heid E, Hornidge D, Jahn O, Kashevarov VL, Knezevic A, Kondratiev R, Korolija M, Kotulla M, Krusche B, Kulbardis A, Lang M, Lisin V, Livingston K, Lugert S, MacGregor IJD, Manley DM, Martinez M, McGeorge JC, Mekterovic D, Metag V, Nefkens BMK, Nikolaev A, Pedroni P, Pheron F, Polonski A, Prakhov SN, Price JW, Rosner G, Rost M, Rostomyan T, Schumann S, Sober D, Starostin A, Supek I, Tarbert CM, Thomas A, Unverzagt M, Walcher T, Watts DP. Beam-helicity asymmetries in double-pion photoproduction off the proton. Phys Rev Lett 2009; 103:052002. [PMID: 19792489 DOI: 10.1103/physrevlett.103.052002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 06/18/2009] [Indexed: 05/28/2023]
Abstract
Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels gamma[over -->]p-->pi(+)pi(0)n, gamma[over -->]p-->pi(0)pi(0)p, and gamma[over -->]p-->pi(+)pi(-)p. The circularly polarized photons, produced from bremsstrahlung of longitudinally polarized electrons, were tagged with the Glasgow magnetic spectrometer. Charged pions and the decay photons of pi(0) mesons were detected in a 4pi electromagnetic calorimeter which combined the Crystal Ball detector with the TAPS detector. The precisely measured asymmetries are very sensitive to details of the production processes and are thus key observables in the modeling of the reaction dynamics.
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Affiliation(s)
- D Krambrich
- Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Mainz, Germany
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Tarbert CM, Watts DP, Aguar P, Ahrens J, Annand JRM, Arends HJ, Beck R, Bekrenev V, Boillat B, Braghieri A, Branford D, Briscoe WJ, Brudvik J, Cherepnya S, Codling R, Downie EJ, Föhl K, Glazier DI, Grabmayr P, Gregor R, Heid E, Hornidge D, Jahn O, Kashevarov VL, Knezevic A, Kondratiev R, Korolija M, Kotulla M, Krambrich D, Krusche B, Lang M, Lisin V, Livingston K, Lugert S, Macgregor IJD, Manley DM, Martinez M, McGeorge JC, Mekterovic D, Metag V, Nefkens BMK, Nikolaev A, Novotny R, Owens RO, Pedroni P, Polonski A, Prakhov SN, Price JW, Rosner G, Rost M, Rostomyan T, Schadmand S, Schumann S, Sober D, Starostin A, Supek I, Thomas A, Unverzagt M, Walcher T, Zehr F. Incoherent neutral pion photoproduction on 12C. Phys Rev Lett 2008; 100:132301. [PMID: 18517938 DOI: 10.1103/physrevlett.100.132301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Indexed: 05/26/2023]
Abstract
We present the first detailed measurement of incoherent photoproduction of neutral pions to a discrete state of a residual nucleus. The 12C(gamma,pi(0))(12)C*(4.4 MeV) reaction has been studied with the Glasgow photon tagger at MAMI employing a new technique which uses the large solid angle Crystal Ball detector both as a pi(0) spectrometer and to detect decay photons from the excited residual nucleus. The technique has potential applications to a broad range of future nuclear measurements with the Crystal Ball and similar detector systems elsewhere. Such data are sensitive to the propagation of the Delta in the nuclear medium and will give the first information on matter transition form factors from measurements with an electromagnetic probe. The incoherent cross sections are compared to two theoretical predictions including a Delta-hole model.
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Affiliation(s)
- C M Tarbert
- School of Physics, University of Edinburgh, Edinburgh, United Kingdom
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Bargiotti M, Bertin A, Bruschi M, Capponi M, De Castro S, Donà R, Fabbri L, Faccioli P, Galli D, Giacobbe B, Marconi U, Massa I, Piccinini M, Semprini Cesari N, Spighi R, Vagnoni V, Vecchi S, Villa M, Vitale A, Zoccoli A, Poli M, Bonomi G, Bussa MP, Corradini M, Lodi Rizzini E, Venturelli L, Zenoni A, Cicalò C, De Falco A, Masoni A, Puddu G, Serci S, Usai G, Gorchakov OE, Prakhov SN, Rozhdestvensky AM, Tretyak VI, Gianotti P, Guaraldo C, Lanaro A, Lucherini V, Petrascu C, Ricci RA, Filippini V, Fontana A, Montagna P, Rotondi A, Salvini P, Balestra F, Cerello P, Denisov O, Ferrero L, Garfagnini R, Grasso A, Maggiora A, Panzarasa A, Panzieri D, Tosello F, Astrua M, Botta E, Bressani T, Calvo D, Feliciello A, Filippi A, Mirfakhrai N, Marcello S, Agnello M, Iazzi F. Protonium annihilation intoπ0π0at rest in a liquid hydrogen target. Int J Clin Exp Med 2001. [DOI: 10.1103/physrevd.65.012001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bertin A, Bruschi M, Capponi M, D'Antone I, Ferretti A, Galli D, Giacobbe B, Marconi U, Piccinini M, Spighi R, Vecchi S, Vezzani A, Vigotti F, Villa M, Vitale A, Zoccoli A, Corradini M, Donzella A, Venturelli L, Zenoni A, Cicalò C, Masoni A, Puddu G, Serci S, Temnikov P, Usai GL, Ableev VG, Denisov OY, Gorchakov OE, Prakhov SN, Rozhdestvensky AM, Sapozhnikov MG, Tretyak W, Poli M, Gianotti P, Guaraldo C, Lanaro A, Lucherini V, Nichitiu F, Petrascu C, Rosca A, Cavion C, Gastaldi U, Lombardi M, Vannucci L, Vedovato G, Morando M, Ricci RA, Bendiscioli G, Filippini V, Fontana A, Montagna P, Rotondi A, Saino A, Salvini P, Balestra F, Botta E, Bressani T, Bussa MP, Busso L, Calvo D. Experimental antiproton nuclear stopping power in H2 and D2. Phys Rev A 1996; 54:5441-5444. [PMID: 9914121 DOI: 10.1103/physreva.54.5441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Ableev V, Adamo A, Agnello M, Balestra F, Belli G, Bendiscioli G, Bertin A, Boccaccio P, Bonazzola GC, Botta E, Bressani T, Bruschi M, Bussa MP, Busso L, Calvo D, Capponi M, Cereda B, Cerello P, Cicalò C, Corradini M, Costa S, De Castro S, De Leo C, Denisov DY, D’Isep F, Donzella A, Fava L, Feliciello A, Ferrero L, Filippi A, Filippini V, Fontana A, Galli TD, Garfagnini R, Gastaldi U, Giacobbe B, Gianotti P, Grasso A, Guaraldo C, Iazzi F, Lanaro A, Rizzini EL, Lombardi M, Lucherini V, Maggiora A, Marcello S, Marconi U, Margagliotti GV, Maron G, Masoni A, Massa I, Minetti B, Montagna P, Morando M, Nichitiu F, Panzieri D, Pauli G, Piccinini M, Piragino G, Poli M, Prakhov SN, Puddu G, Ricci RA, Rossetto E, Rotondi A, Rozhdestvensky AM, Saino A, Salvini P, Santi L, Sapozhnikov MG, Cesari NS, Serci S, Spighi R, Temnikov P, Tessaro S, Tosello F, Tretyak VI, Usai G, Vannucci L, Vecchi S, Vedovato G, Venturelli L, Villa M, Vitale A, Zenoni A, Zoccoli A, Zosi G. Evidence of a new state at ∼ 1660 MeV/c2 observed in $$\bar np$$ annihilationsannihilations. ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf02733990] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bl�mlein J, Brunner J, Grabosch HJ, Lanius P, Nowak S, Rethfeldt C, Ryseck HE, Walter M, Kiss D, Jaki Z, Barabash LS, Baranov SA, Batusov YA, Bunyatov SA, Denisov OY, Gorbunov NV, Karev AG, Kasarinov MY, Klimov OL, Kuznetsov OM, Ladygin EA, Lyukov VV, Mojsenz PV, Obudovski VP, Prakhov SN, Snyatkov VI, Anykeyev VB, Bamburov NS, Borisov AA, Boshko NI, Bugorsky AP, Chernishenko SK, Chukin GL, Fachrutdinov RM, Galjaev NA, Goryachev VN, Kirsanov MM, Koshin AS, Kravtsov VI, Kulikov AV, Lipajev VV, Mukhin AI, Mukhin SA, Ryshenkov VN, Salomatin YI, Sapunov YM, Senko VA, Shestermanov KE, Spiridonov AA, Sytin AN, Sytnik VV, Tumakov VA, Vovenko AS, Zhigunov VP, Zudin YA. Limits on neutral light scalar and pseudoscalar particles in a proton beam dump experiment. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf01548556] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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