Search for the $X(2370)$ and observation of $\hat{I}{\cdot }_c\to \hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime }$ in $J/\ddot{I}ˆ\to {\hat{I}}^3\hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime }$

Abstract

Using a sample of $1.31\times 10^{9}J/\ddot{I}ˆ$ events collected with the BESIII detector, we perform a study of $J/\ddot{I}ˆ\to {\hat{I}}^3\hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime }$ to search for the $X(2370)$ and $\hat{I}{\cdot }_c$ in the $\hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime }$ invariant mass distribution. No significant signal for the $X(2370)$ is observed, and we set an upper limit for the product branching fraction of $\mathcal{B}(J/\ddot{I}ˆ\to {\hat{I}}^{3}X(2370)\cdot \mathcal{B}(X(2370)\to \hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime })<9.2\times 10^{-6}$ at the 90% confidence level. A clear $\hat{I}{\cdot }_c$ signal is observed for the first time, yielding a product branching fraction of $\mathcal{B}(J/\ddot{I}ˆ\to {\hat{I}}^3\hat{I}{\cdot }_c)\cdot \mathcal{B}(\hat{I}{\cdot }_c\to \hat{I}\cdot \hat{I}\cdot \hat{I}{\cdot }^{\prime })=(4.86\pm 0.62(stat.)\pm 0.45(sys.))\times 10^{-5}$.

arXiv admin note: text overlap with arXiv:1912.11253