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S=--1 Meson-Baryon Scattering in Coupled Channel Unitarized Chiral Perturbation Theory

C. Garcia-Recio·J. Nieves·E. Ruiz Arriola·M. Vicente Vacas
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Abstract

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: $\bar K N$, $πΣ$, $ηΛ$, $ K Ξ$. 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 determine masses and widths of the $Λ(1405)$ and $Λ(1670)$ resonances which compare well with accepted numbers.

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C. Garcia-Recio, J. Nieves, E. Ruiz Arriola, M. Vicente Vacas. 2002-09-18. S=--1 Meson-Baryon Scattering in Coupled Channel Unitarized Chiral Perturbation Theory. https://doi.org/10.1140/epja%2Fi2002-10297-y

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