The chiral approach to Meson-Baryon interactions with S = -2

Abstract

We show that two Ξ∗ poles can be dynamically generated in a coupled-channels chiral model with next-to-leading order terms in Lagrangian, focusing on the study of low-energy mesonbaryon scattering in the strangeness S = −2 sector and isospin I = 1/2. One of the resonances found, which has a mass of about 1600 MeV, couples very strongly to the πΞ channel. Consequently, it can be identified as the Ξ(1620) state with JP = 1/2−. The second pole detected, near the ¯K Σ threshold, can be identified as an s-wave ¯K Σ molecular state, which we can associate with the Ξ(1690) resonance assigning it the same quantum numbers as the previous one