Determination of the number of $J/\ddot{I}ˆ$ events with inclusive $J/\ddot{I}ˆ$ decays

Abstract

A measurement of the number of $J/\ddot{I}ˆ$ events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the $J/\ddot{I}ˆ$ . The number of $J/\ddot{I}ˆ$ events taken in 2009 is recalculated to be $(223.7\pm 1.4)\times 10^6$, which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of $J/\ddot{I}ˆ$ events taken in 2012 is determined to be $(1086.9\pm 6.0)\times 10^6$. In total, the number of $J/\ddot{I}ˆ$ events collected with the BESIII detector is measured to be $(1310.6\pm 7.0)\times 10^6$, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.

10 pages, 6 figures