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Jermann N, Krusche B, Metag V, Afzal F, Badea M, Beck R, Bielefeldt P, Bieling J, Biroth M, Blanke E, Borisov N, Bornstein M, Brinkmann KT, Ciupka S, Crede V, Dolzhikov A, Drexler P, Dutz H, Elsner D, Fedorov A, Frommberger F, Gardner S, Ghosal D, Goertz S, Gorodnov I, Grüner M, Hammann C, Hartmann J, Hillert W, Hoffmeister P, Honisch C, Jude TC, Kalischewski F, Ketzer B, Klassen P, Klein F, Klempt E, Knaust J, Kolanus N, Kreit J, Krönert P, Lang M, Lazarev AB, Livingston K, Lutterer S, Mahlberg P, Meier C, Meyer W, Mitlasoczki B, Müllers J, Nanova M, Neganov A, Nikonov K, Noël JF, Ostrick M, Ottnad J, Otto B, Penman G, Poller T, Proft D, Reicherz G, Reinartz N, Richter L, Runkel S, Salisbury B, Sarantsev AV, Schaab D, Schmidt C, Schmieden H, Schultes J, Seifen T, Spieker K, Stausberg N, Steinacher M, Taubert F, Thiel A, Thoma U, Thomas A, Urban M, Urff G, Usov Y, van Pee H, Wang YC, Wendel C, Wiedner U, Wunderlich Y. Measurement of polarization observables T, P, and H in π0 and η photoproduction off quasi-free nucleons. Eur Phys J A Hadron Nucl 2023; 59:232. [PMID: 37860634 PMCID: PMC10582157 DOI: 10.1140/epja/s10050-023-01134-0] [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: 08/04/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023]
Abstract
The target asymmetry T, recoil asymmetry P, and beam-target double polarization observable H were determined in exclusive π 0 and η photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the γ p → π 0 p and γ p → η p reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the η n system at W = 1.68 GeV . A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the S 11 ( 1535 ) and S 11 ( 1650 ) resonances within the S 11 -partial wave.
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Affiliation(s)
- N. Jermann
- Department of Physics, University of Basel, Basel, Switzerland
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - B. Krusche
- Department of Physics, University of Basel, Basel, Switzerland
| | - V. Metag
- II. Physikalisches Institut, University of Giessen, Giessen, Germany
| | - F. Afzal
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Badea
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - R. Beck
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - P. Bielefeldt
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. Bieling
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Biroth
- Institut für Kernphysik, University of Mainz, Mainz, Germany
| | - E. Blanke
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - N. Borisov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - M. Bornstein
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - K.-T. Brinkmann
- II. Physikalisches Institut, University of Giessen, Giessen, Germany
| | - S. Ciupka
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - V. Crede
- Department of Physics, Florida State University, Tallahassee, USA
| | - A. Dolzhikov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - P. Drexler
- Institut für Kernphysik, University of Mainz, Mainz, Germany
| | - H. Dutz
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - D. Elsner
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - A. Fedorov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - F. Frommberger
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - S. Gardner
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - D. Ghosal
- Department of Physics, University of Basel, Basel, Switzerland
- Present Address: resent address: University of Liverpool, Liverpool, UK
| | - S. Goertz
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - I. Gorodnov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - M. Grüner
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - C. Hammann
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. Hartmann
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - W. Hillert
- Physikalisches Institut, University of Bonn, Bonn, Germany
- Present Address: resent address: University of Hamburg, Hamburg, Germany
| | - P. Hoffmeister
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - C. Honisch
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - T. C. Jude
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - F. Kalischewski
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - B. Ketzer
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - P. Klassen
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - F. Klein
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - E. Klempt
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. Knaust
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - N. Kolanus
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. Kreit
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - P. Krönert
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Lang
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | | | - K. Livingston
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - S. Lutterer
- Department of Physics, University of Basel, Basel, Switzerland
- Present Address: resent address: Ruhr University Bochum, Bochum, Germany
| | - P. Mahlberg
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - C. Meier
- Department of Physics, University of Basel, Basel, Switzerland
| | - W. Meyer
- Institut für Experimentalphysik I, Ruhr University Bochum, Bochum, Germany
| | - B. Mitlasoczki
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. Müllers
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Nanova
- II. Physikalisches Institut, University of Giessen, Giessen, Germany
| | - A. Neganov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - K. Nikonov
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - J. F. Noël
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Ostrick
- Institut für Kernphysik, University of Mainz, Mainz, Germany
| | - J. Ottnad
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - B. Otto
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - G. Penman
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - T. Poller
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - D. Proft
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - G. Reicherz
- Institut für Experimentalphysik I, Ruhr University Bochum, Bochum, Germany
| | - N. Reinartz
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - L. Richter
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - S. Runkel
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - B. Salisbury
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - A. V. Sarantsev
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - D. Schaab
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - C. Schmidt
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - H. Schmieden
- Physikalisches Institut, University of Bonn, Bonn, Germany
| | - J. Schultes
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - T. Seifen
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - K. Spieker
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - N. Stausberg
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - M. Steinacher
- Department of Physics, University of Basel, Basel, Switzerland
| | - F. Taubert
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - A. Thiel
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - U. Thoma
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - A. Thomas
- Institut für Kernphysik, University of Mainz, Mainz, Germany
| | - M. Urban
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - G. Urff
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - Y. Usov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - H. van Pee
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - Y. C. Wang
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - C. Wendel
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - U. Wiedner
- Institut für Experimentalphysik I, Ruhr University Bochum, Bochum, Germany
| | - Y. Wunderlich
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
| | - CBELSA/TAPS Collaboration
- Department of Physics, University of Basel, Basel, Switzerland
- Helmholtz-Institut für Strahlen-und Kernphysik, University of Bonn, Bonn, Germany
- II. Physikalisches Institut, University of Giessen, Giessen, Germany
- Institut für Kernphysik, University of Mainz, Mainz, Germany
- Joint Institute for Nuclear Research, Dubna, Russia
- Department of Physics, Florida State University, Tallahassee, USA
- Physikalisches Institut, University of Bonn, Bonn, Germany
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, UK
- Institut für Experimentalphysik I, Ruhr University Bochum, Bochum, Germany
- Present Address: resent address: University of Liverpool, Liverpool, UK
- Present Address: resent address: University of Hamburg, Hamburg, Germany
- Present Address: resent address: Ruhr University Bochum, Bochum, Germany
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Alef S, Bauer P, Bayadilov D, Beck R, Becker M, Bella A, Bielefeldt P, Böse S, Braghieri A, Brinkmann K, Cole P, Di Salvo R, Dutz H, Elsner D, Fantini A, Freyermuth O, Friedrich S, Frommberger F, Ganenko V, Geffers D, Gervino G, Ghio F, Görtz S, Gridnev A, Gutz E, Hammann D, Hannappel J, Hillert W, Ignatov A, Jahn R, Joosten R, Jude T, Klein F, Knaust J, Kohl K, Koop K, Krusche B, Lapik A, Levi Sandri P, Lopatin I, Mandaglio G, Messi F, Messi R, Metag V, Moricciani D, Mushkarenkov A, Nanova M, Nedorezov V, Novinskiy D, Pedroni P, Reitz B, Romaniuk M, Rostomyan T, Rudnev N, Schaerf C, Scheluchin G, Schmieden H, Stugelev A, Sumachev V, Tarakanov V, Vegna V, Walther D, Watts D, Zaunick H, Zimmermann T. Commissioning and initial experimental program of the BGO-OD experiment at ELSA. EPJ Web Conf 2016. [DOI: 10.1051/epjconf/201613007013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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