Jun 13 – 17, 2011
Europe/Berlin timezone
Proceedings are now available online at <a href="http://www.slac.stanford.edu/econf/C110613/">eConf</a>

Photoproduction of η-Mesons off Light Nuclei

Jun 13, 2011, 4:50 PM
Club 3 (Künstlerhaus)

Club 3


talk Light Baryons Light Baryons


Ms Lilian Witthauer (Basel University, Department of Physics)


Recent experiments at the Mainz MAMI and the Bonn ELSA accelerators have studied the excitation spectrum of the nucleon with photoproduction of η-mesons off light target nuclei (2H, 3He). Special attention was given to the photoexcitation of the neutron in order to investigate the isospin structure of electromagnetic resonance couplings. The resulting cross sections shows a narrow in the reaction on the neutron, which is not visible on the proton. This structure was first seen in measurements of the GRAAL-, CBELSA-, and LNS-Sendai collaboration. Recent results of the Mainz A2-collaboration which confirm this structure in new high statistics measurements will be presented. The structure appears in the measurements off neutrons bound in deuterium or 3He in the same way, which makes specific nuclear effects very unlikely. Additionally few nucleon systems as 3He have been used for the investigation of the meson-nucleon and meson-nucleus interactions. Recent results for coherent η-photoproduction off 3He confirm the strong threshold enhancement of this reaction reported from an earlier experiment by M. Pfeiffer et. al. (Phys. Rev. Lett. 92 (2004) 252001) with much better statistical quality. This behaviour gives further evidence for the possible formation of a quasi-bound η nulceus state.

Primary author

Ms Lilian Witthauer (Basel University, Department of Physics)

Presentation materials