S = -1 meson-baryon scattering in coupled-channel unitarized Chiral Perturbation Theory
Departamento de Física Moderna, Universidad de Granada, E-18071, Granada, Spain
2 Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Ap. Correos 22085, E-46071, Valencia, Spain
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The s-wave meson-baryon scattering amplitude is analyzed for the strangeness S = -1 and isospin I = 0 sector in a Bethe-Salpeter coupled-channel formalism incorporating Chiral Symmetry. Four two-body channels have been considered: , , , . The needed two-particle irreducible matrix amplitude is taken from lowest-order Chiral Perturbation Theory in a relativistic formalism. Off-shell behaviour is parameterized in terms of low-energy constants, which outnumber those assumed in previous works and provide a better fit to the data. The position of the complex poles in the second Riemann sheet of the scattering amplitude determines masses and widths of the and resonances which compare well with accepted numbers.
© Società Italiana di Fisica and Springer-Verlag, 2003