BARYON–BARYON INTERACTION IN THE EXTENDED CHIRAL SU(3) QUARK MODEL

The hyperon-nucleon scattering processes and some dibaryon states are studied both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model by solving the resonating group method (RGM) equation. We find that the short-range interaction could be described either by the one-gluon exchange or by the vector meson exchange for baryon-baryon system.

$\bar KN$ SCATTERING IN CHIRAL CONSTITUENT QUARK MODELS

The chiral SU(3) quark model and the extended chiral SU(3) quark model have proven to be quite successful in reproducing the binding energy of the deuteron, the nucleon–nucleon (NN) scattering phase shifts and the hyperon–nucleon (YN) cross-sections. In the chiral SU(3) quark model, the quark–quark interaction contains one-gluon exchange (OGE), confinement potential and boson exchanges stemming from scalar and pseudoscalar nonets. In the extended chiral SU(3) quark model, the OGE is nearly replaced by vector meson exchange. It was shown in our previous work that these two models give quite similar descriptions for the S, P, D, F wave KN phase shifts, which means that in the KN system the contribution of OGE can be replaced by that of vector meson exchange. In this paper, we use the same models, the same parameters and the same methods to study the [Formula: see text] system with the purpose to test the effects of OGE and vector meson exchange. The cross-sections for K-p scattering into K-p, K0n, π+Σ-, π-Σ+, π0Σ0 and π0Λ channels are dynamically calculated by solving the resonating group method equation. While some channels are well described in one or the other model, a good agreement between the theoretical cross-sections and the experimental data for all channels is not successfully obtained. The present work indicates that both OGE and vector meson exchange are necessary to be included in the quark–quark interactions if one tries to simultaneously describe the KN phase shifts and [Formula: see text] cross-sections using one set of parameters in a constituent quark model.

STUDY OF THE PRODUCTION MECHANISM OF THE η MESON BY MEANS OF ANALYSING POWER MEASUREMENTS

Information about the production mechanism of the η meson in proton-proton collisions can be inferred by confronting the experimental studies on the analysing power for the [Formula: see text] reaction with the theoretical predictions of this observable. The determined analysing powers for Q =10 MeV and Q =36 MeV are consistent with zero. Results show that the predictions of pure pseudoscalar meson exchange model fairly describe the experimental data, while the predictions of pure vector meson exchange dominance model disagree with the data at the level of 4.3 σ.