Improved measurement of the decays ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+(0)}{\pi }^{-(0)}$ and search for the rare decay ${\eta }^{\prime }\to 4{\pi }^0$

Abstract

Using a sample of 10 billion $J/\psi$ events collected with the BESIII detector, the decays ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$, ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0$ and ${\eta }^{\prime }\to 4{\pi }^0$ are studied via the process $J/\psi \to \gamma {\eta }^{\prime }$. The branching fractions of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ and ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^0$ ${\pi }^0$ are measured to be $(8.56\pm 0.25(stat.)\pm 0.23(syst.))\times 10^{-5}$ and $(2.12\pm 0.12(stat.)\pm 0.10(syst.))\times 10^{-4}$, respectively, which are consistent with previous measurements but with improved precision. No significant ${\eta }^{\prime }\to 4{\pi }^0$ signal is observed, and the upper limit on the branching fraction of this decay is determined to be less than $1.24\times 10^{-5}$ at the $90\%$ confidence level. In addition, an amplitude analysis of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ is performed to extract the doubly virtual isovector form factor $\alpha$ for the first time. The measured value of $\alpha =1.22\pm 0.33(stat.)\pm 0.04(syst.)$, is in agreement with the prediction of the VMD model.

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• Search for the rare decay ${\eta }^{\prime }\to {\pi }^0{\pi }^0{\pi }^0{\pi }^0$ at BESIII

Cited by in corpus (3)

• Precision evaluation of the $\eta$- and ${\eta }^{\prime }$-pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon
• Study of the decay ψ(3686) \to Σ^{0}\barΣ^{0}ϕ
• Observation of the decay $\psi (3686)\to {\Sigma }^0{\bar{\Sigma }}^0\omega$