Search for Invisible Decays of $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ in $J/\ddot{I}ˆ\to \ddot{I}•\hat{I}\cdot$ and $\ddot{I}•\hat{I}{\cdot }^{\prime }$

Abstract

Using a data sample of $58\times 10^6$ $J/\ddot{I}ˆ$ decays collected with the BES II detector at the BEPC, searches for invisible decays of $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ in $J/\ddot{I}ˆ$ to $\ddot{I}•\hat{I}\cdot$ and $\ddot{I}•\hat{I}{\cdot }^{\prime }$ are performed. The $\ddot{I}•$ signals, which are reconstructed in $K^{+}{K}^{-}$ final states, are used to tag the $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ decays. No signals are found for the invisible decays of either $\hat{I}\cdot$ or $\hat{I}{\cdot }^{\prime }$, and upper limits at the 90% confidence level are determined to be $1.65\times 10^{-3}$ for the ratio $\frac{B(\hat{I}\cdot \to \text{invisible})}{B(\hat{I}\cdot \to {\hat{I}}^3{\hat{I}}^3)}$ and $6.69\times 10^{-2}$ for $\frac{B(\hat{I}{\cdot }^{\prime }\to \text{invisible})}{B(\hat{I}{\cdot }^{\prime }\to {\hat{I}}^3{\hat{I}}^3)}$. These are the first searches for $\hat{I}\cdot$ and $\hat{I}{\cdot }^{\prime }$ decays into invisible final states.

5 pages, 4 figures; Added references, Corrected typos