https://doi.org/10.1140/epja/i2015-15070-7
Regular Article - Theoretical Physics
Eta photoproduction in a combined analysis of pion- and photon-induced reactions
1
Helmholtz-Institut für Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
2
Institute for Nuclear Studies and Department of Physics, The George Washington University, 20052, Washington, DC, USA
3
Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425, Jülich, Germany
4
Institute for Advanced Simulation, Forschungszentrum Jülich, 52425, Jülich, Germany
5
Department of Physics and Astronomy, University of Georgia, 30602, Athens, Georgia, USA
* e-mail: roenchen@hiskp.uni-bonn.de
Received:
7
April
2015
Revised:
8
May
2015
Accepted:
17
May
2015
Published online:
25
June
2015
The ηN final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited Δ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of E ∼ 2.3 GeV is analyzed, including data on differential cross sections, and single- and double-polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions πN → πN, ηN, KΛ and KΣ. For the analysis, the so-called Jülich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. The influence of recent MAMI T and F asymmetry data on the eta photoproduction amplitude is discussed in detail.
© SIF, Springer-Verlag Berlin Heidelberg, 2015
