Number of $\rm J/\psi$ events at BESIII

Abstract

Using inclusive decays of the $\rm J/\psi$, a precise determination of the number of $\rm J/\psi$ events collected with the BESIII detector is performed. For the two data sets taken in 2009 and 2012, the numbers of $\rm J/\psi$ events are recalculated to be $(224.0 \pm 1.3)\times10^6$ and $(1088.5 \pm 4.4)\times10^6$ respectively, which are in good agreement with the previous measurements. For the $\rm J/\psi$ sample taken in 2017--2019, the number of events is determined to be $(8774.0 \pm 39.4)\times10^{6}$. The total number of $\rm J/\psi$ events collected with the BESIII detector is determined to be $(10087 \pm 44)\times10^{6}$, where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.