Determination of the number of $\psi(3686)$ events taken at BESIII

TL;DR

This paper accurately determines the number of $\psi(3686)$ events collected by BESIII in 2021 and updates previous measurements, providing a precise total count across three data sets for future physics analyses.

Contribution

The paper presents a new measurement of $\psi(3686)$ events in 2021 and updates previous counts, improving the precision and consistency of the dataset used in charmonium studies.

Findings

2021 $\psi(3686)$ events: (2259.3 ± 11.1) million

2009 $\psi(3686)$ events: (107.7 ± 0.6) million

2012 $\psi(3686)$ events: (345.4 ± 2.6) million

Abstract

The number of $\psi(3686)$ events collected by the BESIII detector during the 2021 run period is determined to be $(2259.3\pm 11.1)\times 10^6$ by counting inclusive $\psi(3686)$ hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of $\psi(3686)$ events collected during the 2009 and 2012 run periods are updated to be $(107.7\pm0.6)\times 10^6$ and $(345.4\pm 2.6)\times 10^6$, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of $\psi(3686)$ events in the three data samples is $(2712.4\pm14.3)\times10^6$.