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HK: Physik der Hadronen und Kerne

HK 3: Theorie I

HK 3.2: Vortrag

Montag, 19. März 2001, 17:00–17:15, B

Nucleon Physics in the Perturbative Chiral Quark Model — •Valery Lyubovitskij, Thomas Gutsche, and Amand Faessler — Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen, Germany

We apply the perturbative chiral quark model (PCQM) at one loop to analyse low-energy nucleon properties: electromagnetic form factors, meson-nucleon sigma-terms and pion-nucleon scattering. Baryons are described as bound states of valence quarks surrounded by a cloud of Goldstone bosons (π, K, η) as required by chiral symmetry. The model is based on the following guide lines: chiral symmetry constraints, fulfilment of low-energy theorems and proper treatment of sea-quarks, that is meson cloud contributions. Analytic expressions for nucleon observables are obtained in terms of fundamental parameters of low-energy pion-nucleon physics (weak pion decay constant, axial nucleon coupling, strong pion-nucleon form factor) and of only one model parameter (radius of the nucleonic three-quark core). Our results are in good agreement with experimental data and results of other theoretical approaches.