Insight into the Narrow Structure in η Photoproduction on the Neutron from Helicity-Dependent Cross Sections.

Autor: Witthauer L; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Dieterle M; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Abt S; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Achenbach P; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Afzal F; Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany., Ahmed Z; University of Regina, Regina, SK S4S 0A2 Canada., Annand JR; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Arends HJ; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Bashkanov M; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom., Beck R; Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany., Biroth M; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Borisov NS; Joint Institute for Nuclear Research, 141980 Dubna, Russia., Braghieri A; INFN Sezione di Pavia, I-27100 Pavia, Italy., Briscoe WJ; Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA., Cividini F; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Costanza S; INFN Sezione di Pavia, I-27100 Pavia, Italy., Collicott C; Department of Astronomy and Physics, Saint Marys University, Halifax, Nova Scotia B3H 3C3, Canada., Denig A; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Downie EJ; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany.; Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA., Drexler P; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Ferretti-Bondy MI; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Gardner S; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Garni S; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Glazier DI; 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., Glowa D; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom., Gradl W; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Günther M; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Gurevich GM; Institute for Nuclear Research, 125047 Moscow, Russia., Hamilton D; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Hornidge D; Mount Allison University, Sackville, New Brunswick E4L 1E6, Canada., Huber GM; University of Regina, Regina, SK S4S 0A2 Canada., Käser A; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Kashevarov VL; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Kay S; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom., Keshelashvili I; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Kondratiev R; Institute for Nuclear Research, 125047 Moscow, Russia., Korolija M; Rudjer Boskovic Institute, HR 10000 Zagreb, Croatia., Krusche B; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Lazarev AB; Joint Institute for Nuclear Research, 141980 Dubna, Russia., Linturi JM; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Lisin V; Institute for Nuclear Research, 125047 Moscow, Russia., Livingston K; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Lutterer S; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., MacGregor IJ; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Mancell J; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Manley DM; Kent State University, Kent, Ohio 44242-0001, USA., Martel PP; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Metag V; II. Physikalisches Institut, University of Giessen, D-35392 Giessen, Germany., Meyer W; Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany., Miskimen R; University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA., Mornacchi E; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Mushkarenkov A; Institute for Nuclear Research, 125047 Moscow, Russia.; University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA., Neganov AB; Joint Institute for Nuclear Research, 141980 Dubna, Russia., Neiser A; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Oberle M; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Ostrick M; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Otte PB; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Paudyal D; University of Regina, Regina, SK S4S 0A2 Canada., Pedroni P; INFN Sezione di Pavia, I-27100 Pavia, Italy., Polonski A; Institute for Nuclear Research, 125047 Moscow, Russia., Prakhov SN; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany.; University of California at Los Angeles, Los Angeles, California 90095-1547, USA., Rajabi A; University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA., Reicherz G; Institut für Experimentalphysik, Ruhr Universität, 44780 Bochum, Germany., Ron G; Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel., Rostomyan T; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Sarty A; Department of Astronomy and Physics, Saint Marys University, Halifax, Nova Scotia B3H 3C3, Canada., Sfienti C; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Sikora MH; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom., Sokhoyan V; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany.; Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA., Spieker K; Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany., Steffen O; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Strakovski II; Center for Nuclear Studies, The George Washington University, Washington, DC 20052-0001, USA., Strub T; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Supek I; Rudjer Boskovic Institute, HR 10000 Zagreb, Croatia., Thiel A; Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115 Bonn, Germany., Thiel M; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Thomas A; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Unverzagt M; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Usov YA; Joint Institute for Nuclear Research, 141980 Dubna, Russia., Wagner S; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Walford NK; Department of Physics, University of Basel, CH-4056 Basel, Switzerland., Watts DP; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom., Werthmüller D; Department of Physics, University of Basel, CH-4056 Basel, Switzerland.; SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Wettig J; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Wolfes M; Institut für Kernphysik, University of Mainz, D-55099 Mainz, Germany., Zana L; SUPA School of Physics, University of Edinburgh, Edinburgh EEH9 3JZ, United Kingdom.
Jazyk: angličtina
Zdroj: Physical review letters [Phys Rev Lett] 2016 Sep 23; Vol. 117 (13), pp. 132502. Date of Electronic Publication: 2016 Sep 22.
DOI: 10.1103/PhysRevLett.117.132502
Abstrakt: 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.
Databáze: MEDLINE