Measurement of the slope parameter αfor the η\to 3π^0 decay at KLOE

Abstract

We report a preliminary measurement of the slope parameter $\hat{I}\pm$ for the $η\to 3\piz$ decay carried out with KLOE at DA$\hat{I}¦$NE; where $\hat{I}\pm$ is the parameter describing the energy dependence of the square of the matrix element for this decay. By fitting the event density in the Dalitz plot with a collected statistic of 420 pb${}^{-1}$ we determine $\hat{I}\pm =-0.027\pm 0.004(stat{)}_{-0.006}^{+0.004}(syst)$. This result is consistent with current chiral perturbation theory calculations within the unitary approach.

" Contributed paper to Lepton-Photon 2007 ". 5 pages, 4 figures