  The s-wave meson-baryon interaction in the $S = -1$, $S= 0$ and $S= -2$
sectors is studied by means of coupled channels, using the lowest-order chiral
Lagrangian and the N/D method or equivalently the Bethe-Salpeter equation to
implement unitarity.
  This chiral approach leads to the dynamical generation of the $\Lambda
(1405)$, $\Lambda(1670)$ and $\Sigma(1620)$ states for $S = -1$, the
$N^*(1535)$ for $S= 0$ and the $\Xi(1620)$ for $S= -2$. We look for poles in
the complex plane and extract the couplings of the resonances to the different
final states. This allows identifying the $\Lambda (1405)$ and the
$\Lambda(1670)$ resonances with $\bar{K}N$ and $K\Xi$ quasibound states,
respectively. Our results are found to be incompatible with the measured
properties of the $\Xi(1690)$ resonance, thus ruling this state out as the
remaining member of this octet of dynamically generated resonances. We
therefore assign $1/2^-$ for the spin and parity of the $\Xi(1620)$ resonance
as the $S=-2$ member of the lowest-lying $1/2^-$ octet.

Nuclear Theory