We present a measurement of the slope parameter $\alpha$ for the $\eta\to 3\pi^{ 0}$ decay, with the KLOE experiment at the DA$\Phi$NE $\phi$-factory, based on a background free sample of $\sim$ 17 millions $\eta$ mesons produced in $\phi$ radiative decays. By fitting the event density in the Dalitz plot we determine $\alpha = -0.0301 \pm 0.0035\,stat\;_{ -0.0035}^{ +0.0022}\,syst\,$. The result is in agreement with recent measurements from hadro- and photo-production experiments.
Categories: hep-ex