TTP01-36 Determination of the Quadratic Slope Parameter in eta to 3 pi0 Decay

We have determined the quadratic slope parameter alpha for eta to 3 pi0 to be alpha = -0.031(4) from a 99% pure sample of 10^6 eta to 3 pi0 decays produced in the reaction pi- p to n eta close to the eta threshold using the Crystal Ball detector at the AGS. The result is four times more precise than the present world data and disagrees with current chiral perturbation theory calculations by about four standard deviations.