sigma and kappa in Scattering Processes and New pi0 pi0 Phase Shift Data

Abstract

The evidences for sigma(600) and kappa(900) observed in our analyses on the pi pi and K pi 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 pi0 pi0 scattering amplitudes and the I=0 S wave phase shifts are presented. The data have been obtained in the pi-p charge exchange reaction, pi- p --> pi0 pi0 n 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 KKbar threshold are consistent with those of the pi+ pi-, so called, standard data and those of the down-flat solution of the CERN-Cracow-Munich polarization data. The analysis of the pi0 pi0 phase shift data observes sigma(600) with the B-W parameters, M_sigma =588 +- 12 MeV and Gamma_sigma =281 +- 25 MeV, which are in good agreement with those in our analysis on the pi+ pi- data.