Improved measurement of $\ddot{I}ˆ(2S)$ decays into $\ddot{I}{„}^{+}\ddot{I}{„}^{-}$

Abstract

Using 14M $\ddot{I}ˆ(2S)$ events collected at BESII, the branching fraction of $\ddot{I}ˆ(2S)\to \ddot{I}{„}^{+}\ddot{I}{„}^{-}$ is measured to be $B{r}_{\ddot{I}„\ddot{I}„}=(3.10\pm 0.21\pm 0.38)\times 10^{-3}$, where the first error is statistical and the second is systematic.

12 pages, 1 figure