A new unitarization approach incorporated with chiral symmetry is established and applied to study the πK elastic scatterings. We demonstrate that the κ resonance exists, if the scattering length parameter in the I=1/2, J=0 channel does not deviate much from its value predicted by chiral perturbation theory. The mass and width of the κ resonance is found to be M κ = 594 ± 79M eV , Γ κ = 724 ± 332M eV , obtained by fitting the LASS data up to 1430MeV. Better determination to the pole parameters is possible if the chiral predictions on scattering lengths are taken into account.

A new unitarization approach is discussed and applied to study the elastic πK scattering process. The existence of the light κ resonance is firmly established if the scattering length in the I=1/2 channel does not deviate too much from its value obtained from chiral perturbation theory, and a precise determination of the mass and width of the κ resonance requires a precise determination of the scattering length parameter.