Search for $\hat{I}{\cdot }_c(2S)\to p\bar{p}$ and branching fraction measurements of $\ddot{I}{‡}_{cJ}\to p\bar{p}$ via $\ddot{I}ˆ(2S)$ radiative decays

Abstract

Using $(27.12\pm 0.14)\times 10^8$ $\ddot{I}ˆ(2S)$ events collected by the BESIII detector operating at BEPCII, we search for the decay $\hat{I}{\cdot }_c(2S)\to p\bar{p}$ via the process $\ddot{I}ˆ(2S)\to {\hat{I}}^3\hat{I}{\cdot }_c(2S)$, and only find a signal with a significance of $1.7\ddot{I}ƒ$. The upper limit of the product branching fraction at the 90% confidence level is determined to be $\mathcal{B}(\ddot{I}ˆ(2S)\to {\hat{I}}^3\hat{I}{\cdot }_c(2S))\times \mathcal{B}(\hat{I}{\cdot }_c(2S)\to p\bar{p})<2.4\times 10^{-7}$. The branching fractions of $\ddot{I}{‡}_{cJ}\to p\bar{p}(J=0,1,2)$ are also measured to be $\mathcal{B}(\ddot{I}{‡}_{c0}\to p\bar{p})=(2.51\pm 0.02\pm 0.08)\times 10^{-4}$, $\mathcal{B}(\ddot{I}{‡}_{c1}\to p\bar{p})=(8.16\pm 0.09\pm 0.25)\times 10^{-4}$, and $\mathcal{B}(\ddot{I}{‡}_{c2}\to p\bar{p})=(8.33\pm 0.09\pm 0.22)\times 10^{-4}$, where the first uncertainty is statistical and the second systematic.