Observation of the $X(2370)$ and search for the $X(2120)$ in $J/\psi \to \gamma K\bar{K}{\eta }^{\prime }$

Abstract

Using a sample of $1.31\times 10^{9}J/\psi$ events collected with the BESIII detector, we perform a study of $J/\psi \to \gamma K\bar{K}{\eta }^{\prime }$. The $X(2370)$ is observed in the $K\bar{K}{\eta }^{\prime }$ invariant-mass distribution with a statistical significance of 8.3$\sigma$. Its resonance parameters are measured to be $M=2341.6\pm 6.5\text{(stat.)}\pm 5.7\text{(syst.)}$~MeV/$c^2$ and $\Gamma =117\pm 10\text{(stat.)}\pm 8\text{(syst.)}$~MeV. The product branching fractions for $J/\psi \to \gamma X(2370),X(2370)\to K^{+}{K}^{-}{\eta }^{\prime }$ and $J/\psi \to \gamma X(2370),X(2370)\to K_S^0{K}_S^0{\eta }^{\prime }$ are determined to be $(1.79\pm 0.23\text{(stat.)}\pm 0.65\text{(syst.)})\times 10^{-5}$ and $(1.18\pm 0.32text(stat.)\pm 0.39\text{(syst.)})\times 10^{-5}$, respectively. No evident signal for the $X(2120)$ is observed in the $K\bar{K}{\eta }^{\prime }$ invariant-mass distribution. The upper limits for the product branching fractions of $\mathcal{B}(J/\psi \to \gamma X(2120)\to \gamma K^{+}{K}^{-}{\eta }^{\prime })$ and $\mathcal{B}(J/\psi \to \gamma X(2120)\to \gamma K_S^0{K}_S^0{\eta }^{\prime })$ are determined to be $1.49\times 10^{-5}$ and $6.38\times 10^{-6}$ at the 90% confidence level, respectively.

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Cited by in corpus (17)

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• Fully strange tetraquark resonant states as the cousins of $X(6900)$
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• SU(3) analysis of fully-light tetraquarks in heavy meson weak decays
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• Mass spectrum of the $\Omega \bar{\Omega }$ states
• Fully strange tetraquark states via QCD sum rules