Measurements of the Dalitz Plot Parameters for $K^{\pm }\to {\pi }^{\pm }{\pi }^0{\pi }^0$ Decays

Abstract

The $g$, $h$, and $k$ Dalitz plot parameters, which are coefficients in a series expansion of the squared module of the matrix element $|M(u,v){|}^2\propto 1+gu+h{u}^2+k{v}^2$ ($u$, $v$ are invariant variables), have been measured for $K^{\pm }\to {\pi }^{\pm }{\pi }^0{\pi }^0$ decays using $35GeV/c$ hadron beams at the IHEP (Protvino) accelerator. Dependences of parameters and fit quality on the ${\pi }^0{\pi }^0$ mass cut were investigated. The results point to the important role of ${\pi }^{+}{\pi }^{-}\to {\pi }^0{\pi }^0$ charge exchange scattering near the ${\pi }^0{\pi }^0$ mass threshold. The comparison of our data with previous measurements is presented.

8 pages, 5 figures