Determination of the Lightest Strange Resonance K_{0}

ABSTRACT

In this work we present a precise and model-independent dispersive determination from data of the existence and parameters of the lightest strange resonance κ/K_{0}^{*}(700). We use both subtracted and unsubtracted partial-wave hyperbolic and fixed-t dispersion relations as constraints on combined fits to πK→πK and ππ→KK[over ¯] data. We then use the hyperbolic equations for the analytic continuation of the isospin I=1/2 scalar partial wave to the complex plane, in order to determine the κ/K_{0}^{*}(700) and K^{*}(892) associated pole parameters and residues.