Study of photon detection efficiency and position resolution of BESIII electromagnetic calorimeter

TL;DR

This paper evaluates the photon detection efficiency and spatial resolution of the BESIII electromagnetic calorimeter using ISR processes at specific resonances, providing calibration insights.

Contribution

It introduces a method to measure photon detection efficiency and position resolution of the BESIII EMC using ISR events at J/ψ and ψ(3770) resonances.

Findings

Photon detection efficiency characterized at specific resonances.

Spatial resolution quantified in polar and azimuthal angles.

Calibration method improves EMC performance understanding.

Abstract

We study the photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) of the BESIII experiment. The control sample of the initial-state-radiation (ISR) process of $e^+e^-\rightarrow \gamma \mu^+\mu^-$ is used at $J/\psi$ and $\psi(3770)$ resonances for the EMC calibration and photon detection efficiency study. Photon detection efficiency is defined as the predicted photon, obtained by performing a kinematic fit with two muon tracks, matched with real photons in the EMC. The spatial resolution of the EMC is defined as the separation in polar ($\theta$) and azimuthal ($\phi$) angles between charged track and associated cluster centroid on the front face of the EMC crystals.