We report a preliminary measurement of the slope parameter α for the
η→ 3 decay carried out with KLOE at DAΦNE; where α 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 α = -0.027 ± 0.004
(stat) ^+0.004_-0.006 (syst). This result is consistent with current
chiral perturbation theory calculations within the unitary approach.
