Search for the Pentaquark State in $\ddot{I}ˆ(2S)$ and $J/\ddot{I}ˆ$ Decays to $K_S^{0}p{K}^{-}\bar{n}$ and $K_S^0\bar{p}{K}^{+}n$

Abstract

Results are presented on $\ddot{I}ˆ(2S)$ and $J/\ddot{I}ˆ$ hadronic decays to $K_S^{0}p{K}^{-}\bar{n}$ and $K_S^0\bar{p}{K}^{+}n$ final states from data samples of 14 million $\ddot{I}ˆ(2S)$ and 58 million $J/\ddot{I}ˆ$ events accumulated at the BES II detector. No $\hat{I}˜(1540)$ signal, the pentaquark candidate, is observed, and upper limits for $\mathcal{B}(\ddot{I}ˆ(2S)\to \hat{I}˜\bar{\hat{I}}˜\to K_S^{0}p{K}^{-}\bar{n}+K_S^0\bar{p}{K}^{+}n)<0.84\times 10^{-5}$ and $\mathcal{B}(J/\ddot{I}ˆ\to \hat{I}˜\bar{\hat{I}}˜\to K_S^{0}p{K}^{-}\bar{n}+K_S^0\bar{p}{K}^{+}n)<1.1\times 10^{-5}$ at the 90% confidence level are set. For single $\hat{I}˜(1540)$ production, the upper limits determined by our analysis are also on the order of $10^{-5}$ in both $\ddot{I}ˆ(2S)$ and $J/\ddot{I}ˆ$ decays.

13 pages, 6 figures, 2 tables