Three channel model of meson-meson scattering and scalar meson spectroscopy

Abstract

New solutions on the scalar -- isoscalar $\ddot{I}€\ddot{I}€$ phase shifts are analysed together with previous $K\bar{K}$ results using a separable potential model of three coupled channels ($\ddot{I}€\ddot{I}€$, $K\bar{K}$ and an effective $2\ddot{I}€2\ddot{I}€$ system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the $\ddot{I}{€}^{-}{p}_{\uparrow }\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}n$ reaction on a polarized target. A relatively narrow (90 -- 180 MeV) scalar resonance $f_0(1400-1460)$ is found, in contrast to a much broader ($\hat{I}“\approx 500$ MeV) state emerging from the analysis of previous unpolarized target data.

10 Latex pages + 6 postscript figures