Heavy liquid chamber analysis of ηO → 3 π and ηO → γγ decay-modes

Abstract

From 199 η O → 3 π O → 6 γ, 526 η O → π + π − π O and 401 η O → γγ events with all γ-rays reconstructed in a heavy liquid bubble chamber, we obtain direct and independent measurements of the branching ratios: R 1 = Γ( η O → 3 π O )/ Γ( η O → π + π - π O ) = 1.50 -0.29 +0.15 and R 2 = Γ( η O → γγ)/ Γ( η O → π + π - π O ) = 1.72 ± 0.25. We also study the Dalitz-plots for the modes η O → 3π O and η O → π +π -π O, and find no significant variation of the amplitude of the decay η O → 3 π O.