Strange resonance poles from K π 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 ĸ- meson, nowadays known as K(_1)(*) (800), the scalar K(_1)(*) (1430), the K*(892) and K(_1)(*) (1410) vectors, the spin-two K(_1)(*) (1430) as well as the spin-three K(_1)(*) (1780). The parameters will be determined from the pole associated to each resonance by means of an analytic continuation of the Kπ 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 Pade approximants, thus avoiding a particular model for the pole parameterization. We also pay particular attention to the evaluation of uncertainties.