σ and κ in Scattering Processes and New π^0π^0 Phase Shift Data(§2. ππ/Kπ Scattering,Possible Existence of the σ-Meson and Its Implications to Hadron Physics)

Abstract

The evidences for σ(600) and κ(900) observed in our analyses on the ππ and K_π scattering phase shift data are described, briefly. The analysis have been performed by the interfering amplitude method, which satisfies the unitarity requirement, using physically meaningful parameters. The introduction of the negative phase shifts (repulsive force) are essential in the analysis. New data for the π^0π^0 scattering amplitudes and the I=0 S wave phase shifts are presented. The data have been obtained in the π^-p charge exchange reaction, π^-p → π^0π^0n at 9 GeV by the E135 experiment at the KEK PS. The amplitude analysis are performed. The behavior of the I=0 S wave phase shifts below KK^^- threshold are consistent with those of the π^+π^-, so called, standard data and those of the down-flat solution of the CEBN-Cracow-Munich polarization data. The analysis of the π^0π^0 phase shift data observes σ(600) with the B-W parameters, M_σ= 588 ± 12 MeV and Γ_σ= 281 ± 25 MeV, which are in good agreement with those in our analysis on the π^+π^- data.