Measurement of the center-of-mass energies at BESIII via the di-muon process

TL;DR

This paper reports precise measurements of the center-of-mass energies at BESIII using di-muon events, confirming energy stability over several years of data collection.

Contribution

It introduces a method to measure the center-of-mass energies with 0.8 MeV precision using di-muon processes at BESIII.

Findings

Center-of-mass energies measured with 0.8 MeV accuracy.

Energy stability confirmed over the data-taking period.

Supports precise studies of charmonium states.

Abstract

From 2011 to 2014, the BESIII experiment collected about 5 fb$^{-1}$ data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states. By analyzing the di-muon process $e^{+}e^{-}\rightarrow\gamma_{\rm ISR/FSR}\mu^{+}\mu^{-}$, the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV. The center-of-mass energy is found to be stable for most of time during the data taking.