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HK: Hadronen und Kerne

HK 42: Structure of Baryons, Mesons VI, Theory

HK 42.4: Vortrag

Dienstag, 17. März 1998, 18:15–18:30, H

Excited states in the ladder Bethe-Salpeter equation — •S. Ahlig, R. Alkofer, G. Hellstern, and H. Reinhardt — Institute for Theoretical Physics, Auf der Morgenstelle 14, 72076 T"ubingen

In the description of excited states by means of the Bethe-Salpeter equation there are still some basic problems which need to be clarified. As a preliminary step towards a better understanding of excited states of hadrons we investigate the covariant ladder Bethe-Salpeter equation for scalar field theories. The appearance of complex eigenvalues is traced back to the presence of unphysical states. We include self-energies and study the resulting improved ladder approximation. Our results demonstrate the necessity to work within a consistent set of Dyson-Schwinger and Bethe-Salpeter equations. Finally we will comment on excited meson states and on excited baryons within a covariant diquark-quark model.

(*) Supported by BMBF under contract 06TU888.