Dalitz plot analysis of η into 3π final state

The KLOE experiment at the Frascati φ factory DAFNE has collected ∼ 450 pb -1 in the 2001 - 2002 data taking. The study of the η → 3 π dynamics, through a fit to the Dalitz plot density distribution, performed with these data is discussed in this paper. A precise measurement of the 'slope parameters' can improve the knowledge of the decay amplitude and allows to test theoretical predictions at the level of precision needed to extract the quark mass ratio (m2s - m-circumflex2)/ (m2d - m2u) from the decay rate (m-circumflex is the u,d average mass)(Author)