Frankfurt 2014 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 18: Hadronenstruktur und -spektroskopie

HK 18.1: Gruppenbericht

Dienstag, 18. März 2014, 14:00–14:30, HZ 3

Experimental determination of the meson-nucleus potential^⋆ — •Mariana Nanova for the CBELSA/TAPS collaboration — II. Physikalisches Institut, Justus-Liebig-Universität Gießen

The investigation of in-medium properties of mesons is motivated by expectations to find evidence for partial restoration of chiral symmetry. In order to study the meson-nucleus interaction and the in-medium properties of mesons it is important to find experimental approaches to determine the meson-nucleus optical potential. Transparency ratio measurements provide information on the inelastic cross section and in-medium width of mesons and thereby on the imaginary part of the meson-nucleus potential. The real part of the optical potential can be deduced from measurements of the excitation function and momentum distribution which are sensitive to the sign and depth of the potential. Data taken on a carbon target at CB/TAPS@ELSA in 2009 have been analysed to determine the real part of the η^′- and ω-nucleus optical potential. The results are compared to model calculations assuming different scenarios for in-medium η^′ and ω mass shifts. The data for both mesons are consistent with a weakly attractive potential. The formation and population of ω-nucleus and η^′-nucleus bound states will be discussed. In case of the ω meson the in-medium width is larger than the potential depth which hampers a successful identification of ω-mesic states. The relatively small in-medium width of the η^′ meson encourages the search for η^′ bound states.
^⋆Funded by DFG(SFB/TR-16)