Number of $J/\ddot{\mathrm{I}}ˆ$ events at BESIII

Abstract

Using inclusive decays of the $J/\ddot{\mathrm{I}}ˆ$, a precise determination of the number of $J/\ddot{\mathrm{I}}ˆ$ events collected with the BESIII detector is performed. For the two data sets taken in 2009 and 2012, the numbers of $J/\ddot{\mathrm{I}}ˆ$ events are recalculated to be $(224.0\pm 1.3)\times 10^6$ and $(1088.5\pm 4.4)\times 10^6$ respectively, which are in good agreement with the previous measurements. For the $J/\ddot{\mathrm{I}}ˆ$ sample taken in 2017--2019, the number of events is determined to be $(8774.0\pm 39.4)\times 10^6$. The total number of $J/\ddot{\mathrm{I}}ˆ$ events collected with the BESIII detector is determined to be $(10087\pm 44)\times 10^6$, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.

9 pages, 9 figures