Analysis of K\pi-scattering phase shift and existence of \kappa(900)-particle

Abstract

Recently we have shown an evidence for existence of \sigma-particle in the previous works; where the \pi\pi S-wave phase shift is reanalyzed, by introducing a repulsive background suggested by the chiral symmetry, and by applying a new method of Interfering Breit-Wigner Amplitudes. In this work we also show, reanalyzing the K\pi S-wave phase shift from a similar standpoint, an evidence for existence of \kappa(900), possibly to be a member of \sigma-nonet.