Eur. Phys. J. A 10, 447-486
The light-baryon spectrum in a relativistic quark model with instanton-induced quark forces
The strange-baryon spectrum
U. Löring, B.Ch. Metsch and H.R. PetryInstitut für Theoretische Kernphysik, Universität Bonn, Nußallee 14-16, D-53115 Bonn, Germany loering@itkp.uni-bonn.de
(Received: 27 March 2001 Communicated by V.V. Anisovich)
Abstract
This is the third of a series of papers treating light-baryon
resonances up to 3 GeV within a relativistically covariant quark model based
on the Bethe-Salpeter equation with instantaneous two-
and three-body forces. In this last paper we extend our previous work
(U. Löring, B.Ch. Metsch, H.R. Petry, this issue, p. 395) on
non-strange baryons to a prediction of the complete strange-baryon
spectrum and a detailed comparison with experiment. We apply the
covariant Salpeter framework, which we developed in the first
paper (U. Löring, K. Kretzschmar, B.Ch. Metsch, H.R. Petry, Eur. Phys. J. A
10, 309 (2001)), to the specific quark models introduced in our work
published in this issue.
Quark confinement is realized by linearly rising three-body string
potentials with appropriate Dirac structures; to describe the hyperfine
structure of the baryon spectrum we adopt 't Hooft's two-quark residual
interaction based on QCD instanton effects. The
investigation of instanton-induced effects in the baryon mass spectrum plays
a central role in this work. We demonstrate that several prominent features
of the excited strange mass spectrum, e.g. the low positions of the
strange partners of the Roper resonance or the appearance of approximate
"parity doublets" in the 
spectrum, find a natural, uniform
explanation in our relativistic quark model with instanton-induced forces.
11.10.St - Bound and unstable states; Bethe-Salpeter equations.
12.39.Ki - Relativistic quark model.
12.40.Yx - Hadron mass models and calculations.
14.20.-c - Baryons (including antiparticles).
© Società Italiana di Fisica, Springer-Verlag 2001
