Study of the isospin breaking decay y (2175) →φf0 (980) →φηπ0 at BESIII

Abstract

Using the measured branching fraction of the decay J/ψ→ηY(2175)→ηφf0(980)→ηφπ+π- from the BESIII experiment, we estimate branching fraction of J/ψ→ηY(2175)→ηφf0(980)→ηφηπ0 decay, which proceeds via the f0(980)-a00(980) mixing and the π0-η mixing. The branching fraction is predicted to be about O(10-6), which can be accessed with 1010 J/ψ events collected at BESIII. The decay is dominated by the contribution from f0(980)-a00(980) mixing. We find that the interference between the amplitudes due to f0(980)-a00(980) mixing and that due to π0-η mixing is constructive. The branching fraction can be increased by about 10%, owing to the interference effect. We also study the ηπ0 mass squared spectrum and find that a narrow peak due to the f0(980)-a00(980) mixing in the ηπ0 mass squared spectrum should be observed. The observation of this decay in experiment will be helpful to determine the f0(980)-a00(980) mixing intensity and get information about the structures of the light scalar mesons.