Speaker
Description
The Circular Electron–Positron Collider (CEPC) enables high-precision electroweak studies at the 𝑍 pole. We present a simulation-based study of the forward–backward charge asymmetry ($A^\mu_{FB}$) in $e^+e^-\to\mu^+\mu^-$ events using the TDR reference detector. After optimized event selection, the signal efficiency reaches about 90% with negligible background contamination. Signal and background samples are generated including $\gamma^*/Z$ interference and QED radiation, and the simulated asymmetry agrees with the LEP result. Systematic effects from muon identification, background, detector resolution, beam energy spread and beam energy calibration are evaluated. Assuming one month of low-luminosity $Z$-pole running in the first CEPC $ZH$ operation year, corresponding to $4\times10^{10}$ $Z$ bosons, the expected precision on $A^\mu_{FB}$ is $\pm3.1\times10^{-5}$ (stat.) and $\pm2.8\times10^{-5}$ (syst.), improving the LEP accuracy by two orders of magnitude.
