Scalar mesons in eta' -> eta pi0 pi0 decay

Abstract

The decay $\hat{I}{\cdot }^{\prime }\to \hat{I}\cdot \ddot{I}{€}^0\ddot{I}{€}^0$ is studied in the framework of isobar model. It is shown, that good agreement with the experiment is achieved if $a_0$- and $\ddot{I}ƒ$-meson contributions are taken into account. The contribution of $a_0$-meson is dominant, but $\ddot{I}ƒ$-meson is necessary to reproduce the form of experimental Dalitz plot. Instead of usual Breit-Wigner form of $\ddot{I}ƒ$-meson propagator we use parametrization of $\ddot{I}€\ddot{I}€$-amplitude, that satisfies analiticity, crossing, unitarity and chirality constraints. This amplitude has a pole in complex plane, that corresponds to $\ddot{I}ƒ$-meson and describe experimental data on $\ddot{I}€\ddot{I}€$-scattering in $K_{e4}$ decay.

6 pages, 4 figures. The text is extended. Errors in figures are corrected, some refreces added