Precision measurement of the η → π+π-π0 Dalitz plot distribution with the KLOE detector

Using 1.6 fb(-1) of e(+)e(-) -> phi -> eta gamma data collected with the KLOE detector at DA Phi NE, the Dalitz plot distribution for the eta -> pi(+)pi(-)pi(0) decay is studied with the world's largest sample of similar to 4.7 . 10(6) events. The Dalitz plot density is parametrized as a polynomial expansion up to cubic terms in the normalized dimensionless variables X and Y. The experiment is sensitive to all charge conjugation conserving terms of the expansion, including a gX(2)Y term. The statistical uncertainty of all parameters is improved by a factor two with respect to earlier measurements.