Study of $J/\ddot{I}ˆ\to p\bar{p}\ddot{I}•$ at BESIII

Abstract

Using a data sample of $1.31\times 10^9$ $J/\ddot{I}ˆ$ events accumulated with the BESIII detector, the decay $J/\ddot{I}ˆ\to p\bar{p}\ddot{I}•$ is studied via two decay modes, $\ddot{I}•\to K_S^0{K}_L^0$ and $\ddot{I}•\to K^{+}{K}^{-}$. The branching fraction of $J/\ddot{I}ˆ\to p\bar{p}\ddot{I}•$ is measured to be $\mathcal{B}(J/ψ\to p\bar{p}ϕ)=[5.23\pm0.06(\mbox{stat})\pm0.33(\mbox{syst})]\times10^{-5}$, which agrees well with a previously published measurement, but with a significantly improved precision. No evident enhancement near the $p\bar{p}$ mass threshold, denoted as $X(p\bar{p})$, is observed, and the upper limit on the branching fraction of $J/\ddot{I}ˆ\to X(p\bar{p})\ddot{I}•\to p\bar{p}\ddot{I}•$ is determined to be $\mathcal{B}(J/\ddot{I}ˆ\to X(p\bar{p})\ddot{I}•\to p\bar{p}\ddot{I}•)<2.1\times 10^{-7}$ at the 90\% confidence level.

9 pages, 4 figures