Journal Article

PreJuSER-33092

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Exclusive measurement of quasi-free eta-photoproduction from deuterium

Weiß, J.FZJ* ; Achenbach, P.FZJ* ; Beck, R.FZJ* ; Hejny, V.FZJ* ; Kleber, V.FZJ* ; Kotulla, M.FZJ* ; Krusche, B.FZJ* ; Kuhr, V. G.FZJ* ; Leukel, R.FZJ* ; Metag, V.FZJ* ; Olmos de Leon, V. M.FZJ* ; Owens, R. O.FZJ* ; Rambo, F.FZJ* ; Schmidt, A.FZJ* ; Siodlaczek, U.FZJ* ; Ströher, H.FZJ* ; Wissmann, F.FZJ* ; Wolf, M.FZJ*

2003
Springer Berlin

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Please use a persistent id in citations: http://hdl.handle.net/2128/10714  doi:10.1140/epja/i2002-10085-9

Abstract: Quasi-free photoproduction of eta-mesons from the deuteron has been measured at the tagged photon facility of the Mainz microtron MAMI with the photon spectrometer TAPS for incident photon energies from the production threshold at 630 MeV up to 820 MeV. In a fully exclusive measurement eta-mesons and recoil nucleons were detected in coincidence. At incident photon energies above the production threshold on the free nucleon, where final-state interaction effects are negligible, an almost constant ratio of sigma(n)/sigma(p) = 0.66 +/- 0.10 was found. At lower incident photon energies the ratio rises due to re-scattering effects. The average ratio agrees with the value extracted from a comparison of the inclusive d(gamma,eta)X cross section to the free-proton cross-section via a participant-spectator model for the deuteron cross-section (sigma(n)/sigma(p) = 0.67 +/- 0.07). The angular dependence of the ratio agrees with the expected small deviation of neutron and proton cross-section from isotropy due to the influence of the D-13(1520)-resonance. The energy dependence of the ratio in the excitation energy range of the S-11(1535)-resonance disfavors model predictions which try to explain this resonance as KSigma bound state.

Keyword(s): photon deuteron: interaction ; photon p: interaction ; photon n: interaction ; photon: tagged beam ; nucleon: recoil ; eta: photoproduction ; channel cross section: ratio ; angular dependence ; energy dependence ; multiple scattering ; model: spectator ; nucleon resonance: effect ; spectrometer: experimental results ; Mainz Linac ; photon deuteron --> eta anything ; photon deuteron --> eta n p ; 0.63-0.82 GeV

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Institut 2 (Experimentelle Kernphysik II) (IKP-E-2)

Research Program(s):

1. Physik der Hadronen (M01)

Appears in the scientific report 2003

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Database coverage:

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