Observation of $\psi (3686)\to \gamma \eta (1405)$ via $\eta (1405)\to f_0(980){\pi }^0$

Abstract

The decay $\psi (3686)\to \gamma {\pi }^{+}{\pi }^{-}{\pi }^0$ is studied using a sample of $(2712.4\pm 14.3)\times 10^6$ $\psi (3686)$ events collected with the BESIII detector. The decay $\eta (1405)\to {\pi }^{+}{\pi }^{-}{\pi }^0$ is observed for the first time in $\psi (3686)$ decays via the intermediate state $f_0(980)$ and the product branching fraction $\mathcal{B}(\psi (3686)\to \gamma \eta (1405))\times \mathcal{B}(\eta (1405)\to f_0(980){\pi }^0)\times \mathcal{B}(f_0(980)\to {\pi }^{+}{\pi }^{-})$ is determined to be $(3.77\pm 0.43\pm 0.29)\times 10^{-7}$, where the first uncertainty is statistical and the second is systematic. The isospin-violating decay of $\psi (3686)\to \gamma f_1(1285)\to \gamma f_0(980){\pi }^0\to \gamma {\pi }^{+}{\pi }^{-}{\pi }^0$ has been observed with signal significance of $2.9\sigma$. And the branching fraction $\mathcal{B}(\psi (3686)\to \gamma f_1(1285)\to \gamma f_0(980){\pi }^0\to \gamma {\pi }^{+}{\pi }^{-}{\pi }^0)$ is determined to be $(7.36\pm 2.25\pm 2.26)\times 10^{-8}$. Since no ${\eta }_c$ signal is evident in either the ${\pi }^{+}{\pi }^{-}{\pi }^0$ or $f_0(980){\pi }^0$ mass spectrum, upper limits are set to be $\mathcal{B}(\psi (3686)\to \gamma {\eta }_c)\times \mathcal{B}({\eta }_c\to {\pi }^{+}{\pi }^{-}{\pi }^0)<3.09\times 10^{-7}$ and $\mathcal{B}(\psi (3686)\to \gamma {\eta }_c)\times \mathcal{B}({\eta }_c\to f_0(980){\pi }^0)\times \mathcal{B}(f_0(980)\to {\pi }^{+}{\pi }^{-})<7.97\times 10^{-8}$ at 90\% confidence level, respectively.

arXiv comment11 pages, 3 figures

References in corpus (24)

• Design and Construction of the BESIII Detector
• The Precision Monte Carlo Event Generator KK For Two-Fermion Final States In e+e- Collisions
• Coherent Exclusive Exponentiation For Precision Monte Carlo Calculations
• Future Physics Programme of BESIII
• Search for hadronic transition ${\chi }_{cJ}\to {\eta }_c{\pi }^{+}{\pi }^{-}$ and observation of ${\chi }_{cJ}\to K\bar{K}\pi \pi \pi$
• Study of ${\chi }_{cJ}$ radiative decays into a vector meson
• The puzzle of anomalously large isospin violations in $\eta (1405/1475)\to 3\pi$
• First observation of $\eta (1405)$ decays into $f_0(980){\pi }^0$
• An amplitude analysis of the ${\pi }^0{\pi }^0$ system produced in radiative $J/\psi$ decays
• Study of $J/\psi$ and $\psi (3686)$ decay to $\Lambda \bar{\Lambda }$ and ${\Sigma }^0{\bar{\Sigma }}^0$ final states
• Determination of the number of $\psi (3686)$ events taken at BESIII
• Observation of B^0_(s) -> J/ψf_1(1285) decays and measurement of the f_1(1285) mixing angle
• Ratio of Hadronic Decay Rates of Jψand ψ(2S) and the ρπPuzzle
• Observation of $a_0^0(980)$-$f_0(980)$ Mixing
• Open charm effects in the explanation of the long-standing "$\rho \pi$ puzzle"
• Internal particle width effects on the the triangle singularity mechanism in the study of the $\eta (1405)$ and $\eta (1475)$ puzzle
• Observation of ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ and ${\eta }^{\prime }\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0$
• The $K\bar{K}\pi$ decay of the $f_1(1285)$ and its nature as a $K^{\ast }\bar{K}-cc$ molecule
• Observation of the isospin-violating decay $J/\psi \to \varphi {\pi }^0{f}_0(980)$
• Isotopic Symmetry Breaking in the $\eta (1405)\to f_0(980){\pi }^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$. Decay through a $K\bar{K}$ Loop Diagram and the Role of Anomalous Landau Thresholds
• Three-body unitary coupled-channel approach to radiative $J/\psi$ decays and $\eta (1405/1475)$
• Search for $\psi (3686)\to \gamma {\eta }_c(\eta (1405))\to \gamma {\pi }^{+}{\pi }^{-}{\pi }^0$
• Three-Body Unitary Coupled-Channel Analysis on $\eta (1405/1475)$
• Measurement of Branching Fractions of $J/\psi$ and $\psi (3686)$ decays to ${\Sigma }^{+}$ and ${\overline{\Sigma }}^{-}$