Observation of J/ψ → pp¯a0(980) at BESIII

Abstract

Using 2.25 × 108, J/ψ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process J/ψ → pp¯a0(980), a0(980) → π0η with a significance of 6.5σ (3.2σ including systematic uncertainties). The product branching fraction of J/ψ → pp¯a0 (980) → pp¯ π0η is measured to be (6.8 ± 1.2 ± 1.3) × 10-5, where the first error is statistical and the second is systematic. This measurement provides information on the a0 production near threshold coupling to pp and improves the understanding of the dynamics of J/ψ decays to four-body processes.