Search for new hadronic decays of $h_c$ and observation of $h_c\to p\bar{p}\hat{I}\cdot$

Abstract

A search for the hadronic decays of the $h_c$ meson to the final states $p\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0$, $p\bar{p}\hat{I}\cdot$, and $p\bar{p}\ddot{I}{€}^0$ via the process $\ddot{I}ˆ(3686)\to \ddot{I}{€}^0{h}_c$ is performed using $(4.48\pm 0.03)\times 10^8$ $\ddot{I}ˆ(3686)$ events collected with the BESIII detector. The decay channel $h_c\to p\bar{p}\hat{I}\cdot$ is observed for the first time with a significance greater than $5\ddot{I}ƒ$ and a branching fraction of $\left(6.41\pm 1.74\pm 0.53\pm 1.00\right)\times 10^{-4}$, where the uncertainties are statistical, systematic, and that from the branching fraction of $\ddot{I}ˆ(3686)\to \ddot{I}{€}^0{h}_c$. Strong evidence for the decay $h_c\to p\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0$ is found with a significance of $4.9\ddot{I}ƒ$ and a branching fraction of $\left(3.84\pm 0.83\pm 0.69\pm 0.58\right)\times 10^{-3}$. The significances include systematic uncertainties. No clear signal of the decay $h_c\to p\bar{p}\ddot{I}{€}^0$ is found, and an upper limit of $6.59\times 10^{-4}$ on its branching fraction is set at the 90% confidence level.