Scalar mesons in eta' -> eta pi0 pi0 decay

Abstract

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

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