Strange resonance poles from $K\pi$ scattering below 1.8 GeV

Abstract

In this work we present a determination of the mass, width and coupling of the resonances that appear in kaon-pion scattering below 1.8 GeV. These are: the much debated scalar $\kappa$-meson, nowdays known as $K_0^{\ast }(800)$, the scalar $K_0^{\ast }(1430)$, the $K^{\ast }(892)$ and $K_1^{\ast }(1410)$ vectors, the spin-two $K_2^{\ast }(1430)$ as well as the spin-three $K_3^{\ast }(1780)$. The parameters will be determined from the pole associated to each resonance by means of an analytic continuation of the $K\pi$ scattering amplitudes obtained in a recent and precise data analysis constrained with dispersion relations, which were not well satisfied in previous analyses. This analytic continuation will be performed by means of Padé approximants, thus avoiding a particular model for the pole parameterization. We also pay particular attention to the evaluation of uncertainties.

Comments: 13 pages, 12 figures. Accepted version to appear in Eur. Phys. J. C. Clarifications and references added, minor typos corrected