Study of Jψdecaying into ωp \bar p

Abstract

The decay $J/\ddot{I}ˆ\to \ddot{I}‰p\bar{p}$ is studied using a $5.8\times 10^7$ $J/\ddot{I}ˆ$ event sample accumulated with the BES II detector at the Beijing electron-positron collider. The decay branching fraction is measured to be $B(J/\ddot{I}ˆ\to \ddot{I}‰p\bar{p})=(9.8\pm 0.3\pm 1.4)\times 10^{-4}$. No significant enhancement near the $p\bar{p}$ mass threshold is observed, and an upper limit of $B(J/\ddot{I}ˆ\to \ddot{I}‰X(1860))B(X(1860)\to p\bar{p})$$<1.5\times 10^{-5}$ is determined at the 95% confidence level, where X(1860) designates the near-threshold enhancement seen in the $p\bar{p}$ mass spectrum in $J/\ddot{I}ˆ\to {\hat{I}}^{3}p\bar{p}$ decays.

5 pages, 4 figures