Hadronic decays of N and Δ resonances in a chiral quark model

Abstract

π and η decay modes of light baryon resonances are investigated within a chiral quark model whose hyperfine interaction is based on Goldstone-boson exchange. For the decay mechanism a modified version of the 3 P0 model is employed. Our primary aim is to provide a further test of the recently proposed Goldstone-boson-exchange constituent quark model. We compare the predictions for π and η decay widths with experiment and also with results from a traditional one-gluon-exchange constituent quark model. The differences between nonrelativistic and semirelativistic versions of the constituent quark models are outlined. We also discuss the sensitivity of the results on the parametrization of the meson wave function entering the 3 P0 model.

Covariant calculation of nonstrange decays of strange baryon resonances

“…Upon calculating their π decay widths we find the predictions as given under the entries of Σ(1750) 2 and Σ(1750) 3 in Table I. Surprisingly, the theoretical results for the [26] and the OGE CQM [20] in comparison to experiment. The first three columns classify the decaying resonance according to the PDG [37].…”

“…[20] and [26], respectively. The shadowed boxes represent the experimental values with their uncertainties [37].…”

“…This is unfortunate, not only in view of the vast amount of experimental data but also because the decay properties of hadron resonances give important insights into strong interaction physics (see, for example, the recent NSTAR workshops [1,2,3]). Investigations of strong decay processes date back to the late 1960s [4,5,6,7,8], and with the refinement of constituent quark models (CQMs) various aspects of the strong decays have been studied [9,10,11,12,13,14,15,16,17,18,19,20]. In particular, the decay mechanism and the type of hyperfine interactions in CQMs have been in the focus of interest.…”

Strangeness production on the nucleon

“…Most CQM's that study hadronic decays of baryon resonances (for a recent example see Ref. [94]), start from a transition operator at quark level which does not contain isospin-dependent terms. In such a model, the amplitude for a pseudo-scalar hadronic decay of a non-strange baryon into a KY-system of the type:…”

K-Λ and K-Σ photo-production in a coupled channels framework

“…These extracted parameters serve as a test of different QCD-based models [1,2]. As will be demonstrated in this work, coupled channels effects are large and should be taken into account in extracting resonance parameters for the higher-lying resonances.…”