München 2006 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 8: Elektromagnetische und Hadronische Sonden
HK 8.3: Vortrag
Montag, 20. März 2006, 17:00–17:15, F
η and π0π0 photoproduction from complex nuclei — •Thierry Mertens — Basel University, Physic institut, Switzerland
Total photoproduction on the free nucleon shows a bump-like structure around 800 MeV, attributed mainly to the excitation of the D13(1520) and the S11(1535) resonances. Its disappearance for nucleus targets could indicate in-medium modifications of the resonances. Self-consistent calculations of the in-medium spectral functions of mesons and nucleons resonances predict almost no effect on the S11 but a strong broadening of the D13 due to its strong coupling to the ρ. Experimentally those properties can be compared via the study of η (dominated by S11) and double π0 (dominated by D13) photoproduction from nuclei. Measurements for carbon, calcium, niobium and lead targets have been done at the ELSA accelerator with the combined Crytall Barrel and Taps detectors. Final results will be discussed in view of the resonance in-medium properties.