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

TL;DR

This paper determines the properties of various kaon-pion resonances below 1.8 GeV using analytic continuation of scattering amplitudes via Padé approximants, providing more precise and model-independent resonance parameters.

Contribution

It introduces a model-independent method using Padé approximants for extracting resonance poles from scattering data constrained by dispersion relations.

Findings

Resonance parameters for multiple kaon-pion states are precisely determined.

The method reduces model dependence in resonance analysis.

Uncertainties in pole extractions are carefully evaluated.

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 $K_0^*(800)$, the scalar $K_0^*(1430)$, the $K^*(892)$ and $K_1^*(1410)$ vectors, the spin-two $K_2^*(1430)$ as well as the spin-three $K^*_3(1780)$. 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 Pad\'e approximants, thus avoiding a particular model for the pole parameterization. We also pay particular attention to the evaluation of uncertainties.