BLED WORKSHOPS
IN PHYSICS
VOL. 1, NO. 1
Proceedins of the Mini-Workshop
Few-Quark Problems (p. 63)
Bled, Slovenia, July 8-15, 2000
News from the Goldstone-Boson-Exchange Chiral
Quark Model
Willibald Plessas?
Institute for Theoretical Physics, University of Graz, Universitätsplatz 5, A-8010 Graz,
Austria
The chiral constituent quark model based on Goldstone-boson-exchange as the
effective hyperfine interaction between constituent quarks has performedwell for
the description of the spectroscopy of all light and strange baryons [1]. Originally
the model was constructed with the spin-spin component of the pseudoscalar
exchange only [2]. Recently it has been extended to include all force components
(central, tensor, spin-orbit) and furthermore vector and scalar exchanges [3,4].
Also, rigorous semirelativistic solutions of the three-quark problem have been
provided [5]. We discuss the present status of the development of the Goldstone-
boson-exchange chiral quark model.
Themodel, in different variants, has already been applied (by several groups)
to various problems beyond baryon spectroscopy. One has thus obtained valu-
able insight into its performance more generally in low- and intermediate-energy
hadron processes. We summarize the corresponding results and discuss them in
comparison to other constituent quark models and/or (effective) approaches to
low-energy QCD.
References
1. L.Ya. Glozman, Z. Papp, W. Plessas, K. Varga, and R.F. Wagenbrunn: Effective Q-Q inter-
actions in constituent quark models, Phys. Rev. C 57, 3406 (1998).
2. L.Ya. Glozman, W. Plessas, K. Varga, and R.F. Wagenbrunn: Unified description of light-
and strange-baryon spectra, Phys. Rev D 58, 094030 (1998).
3. R.F. Wagenbrunn, L.Ya. Glozman, W. Plessas, and K. Varga: Goldstone-boson-exchange
dynamics in the constituent-quark model for baryons, Few-Body Systems Suppl. 10, 387
(1999).
4. R.F. Wagenbrunn, L.Ya. Glozman, W. Plessas, and K. Varga: Semirelativistic constituent-
quark model with Goldstone-boson-exchange hyperfine interactions, Few-Body Systems
Suppl. 11, 25 (1999).
5. Z. Papp, A. Krassnigg, and W. Plessas: Faddeev approach to confined three-quark problems,
Preprint nucl-th/0002006.
? E-mail: plessas@bkfug.kfunigraz.ac.at