Three channel model of meson meson scattering and scalar meson spectroscopy

Abstract New solutions on the scalar-isoscalar ππ phase shifts are analysed together with previous K K results using a separable potential model of three coupled channels (ππ, K K and an effective 2π2π system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the π−p↑ → π+π−n reaction on a polarized target. A relatively narrow (90–180 MeV) scalar resonance f0(1400–1460) is found, in contrast to a much broader (Γ ≈ 500 MeV) state emerging from the analysis of previous unpolarized target data.