The $\ddot{I}ƒ$ pole in $J/\ddot{I}ˆ\to \ddot{I}‰\ddot{I}{€}^{+}\ddot{I}{€}^{-}$

Abstract

Using a sample of 58 million $J/\ddot{I}ˆ$ events recorded in the BESII detector, the decay $J/\ddot{I}ˆ\to \ddot{I}‰\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ is studied. There are conspicuous $\ddot{I}‰f_2(1270)$ and $b_1(1235)\ddot{I}€$ signals. At low $\ddot{I}€\ddot{I}€$ mass, a large broad peak due to the $\ddot{I}ƒ$ is observed, and its pole position is determined to be $(541\pm 39)$ - $i$ $(252\pm 42)$ MeV from the mean of six analyses. The errors are dominated by the systematic errors.

15 pages, 6 figures, submitted to PLB