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

TL;DR

This paper precisely determines the total number of $\psi(3686)$ events collected by BESIII in 2009 and 2012, providing essential data for subsequent physics analyses with minimal statistical uncertainty.

Contribution

The paper presents a new, accurate measurement of $\psi(3686)$ event counts at BESIII, improving the precision over previous estimates and combining data from two different periods.

Findings

Total $\psi(3686)$ events: $(448.1\pm 2.9) imes 10^6$

Event counts for 2009 and 2012 are $(107.0\pm 0.8) imes 10^6$ and $(341.1\pm 2.1) imes 10^6$

Uncertainty dominated by systematics, negligible statistical error.

Abstract

The numbers of $\psi(3686)$ events accumulated by the BESIII detector for the two rounds of data taking during 2009 and 2012 are determined to be $(107.0\pm0.8)\times 10^6$ and $(341.1\pm 2.1)\times 10^6$, respectively, by counting inclusive hadronic events, where the uncertainty is dominated by systematics and the statistical uncertainty is negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of $\psi(3686)$ events for the two data-taking periods is $(448.1\pm2.9)\times10^6$.