Search for the rare decay η′ →π0π0π0π0 at BESIII

Abstract

Using a sample of 1.31×109 J/ψ events collected with the BESIII detector, we perform a search for the rare decay η′→4π0 via J/ψ→γη′. No significant η′ signal is observed in the 4π0 invariant mass spectrum. With a Bayesian approach, the upper limit on the branching fraction is determined to be B(η′→4π0)<4.94×10-5 at the 90% confidence level, which is a factor of 6 smaller than the previous experimental limit.