Photoproduction of η mesons from the neutron: Cross sections and double polarization observable E
Creators
- Witthauer, L.1
- Dieterle, M.1
- Challand, T.1
- Kaeser, A.1
- Keshelashvili, I.1
- Krusche, B.1
- Rostomyan, T.1
- Walford, N.K.1
- Werthmueller, D.1
- Afzal, F.2
- Beck, R.2
- Boese, S.2
- Funke, C.2
- Gottschall, M.2
- Gruener, M.2
- Hammann, C.2
- Hartmann, J.2
- Hoffmeister, P.2
- Honisch, C.2
- Kaiser, D.2
- Kalinowsky, H.2
- Kalischewski, F.2
- Klassen, P.2
- Koop, K.2
- Lang, M.2
- Mahlberg, P.2
- Mueller, J.2
- Muellers, J.2
- Piontek, D.2
- Schmidt, C.2
- Seifen, T.2
- Sokhoyan, V.2
- Spieker, K.2
- Thiel, A.2
- Thoma, U.2
- Urban, M.2
- Pee, H. van2
- Walther, D.2
- Wendel, C.2
- Winnebeck, A.2
- Anisovich, A.V.3, 2
- Bayadilov, D.3, 2
- Nikonov, V.3, 2
- Sarantsev, A.3, 2
- Bantes, B.4
- Dutz, H.4
- Eberhardt, H.4
- Elsner, D.4
- Ewald, R.4
- Fornet-Ponse, K.4
- Frommberger, F.4
- Goertz, S.4
- Hammann, D.4
- Hannappel, J.4
- Hillert, W.4
- Jude, T.4
- Kammer, S.4
- Kleber, V.4
- Klein, F.4
- Schmieden, H.4
- Bichow, M.5
- Meyer, W.5
- Reicherz, G.5
- Brinkmann, K.T.6, 2
- Gutz, E.6, 2
- Crede, V.7
- Friedrich, S.6
- Makonyi, K.6
- Metag, V.6
- Nanova, M.6
- Gridnev, A.3
- Lopatin, I.3
- Wilson, A.7, 2
- The CBELSA/TAPS Collaboration
- 1. University of Basel, Department of Physics, Basel (Switzerland)
- 2. Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany)
- 3. Petersburg Nuclear Physics Institute, National Research Centre ''Kurchatov Institute'', Gatchina (Russian Federation)
- 4. Universitaet Bonn, Physikalisches Institut, Bonn (Germany)
- 5. Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany)
- 6. Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany)
- 7. Florida State University, Department of Physics, Tallahassee, FL (United States)
Description
Results from measurements of the photoproduction of η mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the η → 3π0 → 6γ decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of γn → nη. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow P11 state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable E. Both data sets together were also used to extract the helicity-dependent cross sections σ1/2 and σ3/2. The narrow structure in the excitation function of γn → nη appears associated with the helicity-1/2 component of the reaction. (orig.)
Availability note (English)
Available from: http://dx.doi.org/10.1140/epja/i2017-12247-0Additional details
Identifiers
Publishing Information
- Journal Title
- European Physical Journal. A
- Journal Volume
- 53
- Journal Issue
- 3
- Journal Page Range
- p. 1-25
- ISSN
- 1434-6001
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 48053519
- Subject category
- S72: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS;
- Resource subtype / Literary indicator
- Numerical Data
- Descriptors DEI
- ANGULAR DISTRIBUTION; ASYMMETRY; ETA MESONS; EXCLUSIVE INTERACTIONS; EXPERIMENTAL DATA; GEV RANGE 01-10; INTEGRAL CROSS SECTIONS; LIQUIDS; MESONS; MEV RANGE 100-1000; NEUTRONS; PHOTON-NEUTRON INTERACTIONS; PHOTON-PROTON INTERACTIONS; PHOTOPRODUCTION; POLARIZATION-ASYMMETRY RATIO; POLARIZED BEAMS; POLARIZED TARGETS; PROTONS; SPIN ORIENTATION
- Descriptors DEC
- BARYONS; BEAMS; BOSONS; CROSS SECTIONS; DATA; DIMENSIONLESS NUMBERS; DISTRIBUTION; ELECTROMAGNETIC INTERACTIONS; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; FLUIDS; FUNDAMENTAL INTERACTIONS; GEV RANGE; HADRONS; INFORMATION; INTERACTIONS; MESONS; MEV RANGE; NUCLEONS; NUMERICAL DATA; ORIENTATION; PARTICLE INTERACTIONS; PARTICLE PRODUCTION; PHOTON-BARYON INTERACTIONS; PHOTON-HADRON INTERACTIONS; PHOTON-NUCLEON INTERACTIONS; PSEUDOSCALAR MESONS; TARGETS
Optional Information
- Collaborations
- The CBELSA/TAPS Collaboration