Search

Λ(1405) is investigated as a resonance in a coupled channel baryon-meson $\Sigma \pi - {\rm{N}}\overline {\rm{K}} - \Lambda \eta$ scattering with a 'bound state embedded in the continuum' (BSEC). This BSEC is introduced by hand, as a state not originated from a simple baryon-meson system. We assume it comes from the three-quark state. There appears a resonance of a large width in the Σπ scattering below the ${\rm{N}}\overline{\rm{K}}$ threshold by assuming the baryon meson interaction whose channel dependence is (1) flavor-flavor type like the chiral unitary approach, (2) flavor-flavor type with a lower-momentum cut-off, or (3) the same as that of the quark cluster model. It is necessary to introduce a BSEC for the latter two cases in order to reproduce the peak. The calculation including a BSEC seems to be preferable to reproduce the ${\rm{N}}\overline{\rm{K}}$ scattering length. Our calculation gives the observed value when the BSEC contribution to the resonance is roughly half of that of the ${\rm{N}}\overline{\rm{K}}$ channel. [ABSTRACT FROM AUTHOR]

We investigate the structure of the SU(3) octet and decuplet baryons employing a constituent chiral quark model. We study the ground, s-wave and p-wave excited states of the three-quark system with many range gaussian bases. The method, which we employ here, is shown to work quite well in describing the structure of the SU(3) s-wave and pwave baryons. It is found that the mass differences between positive and negative parity states are well reproduced. It is also found that the pseudoscalar (ps) meson exchange potential plays a very important role in describing the mass of the nucleon resonance N[sup *](1440) (roper). We also discuss how the semirelativistic approach works in the chiral quark model, and how to treat the potential terms in the semirelativistic approach. [ABSTRACT FROM AUTHOR]