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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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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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