Prospects for detecting axion-like particles via the decay $Z\rightarrow af\bar{f}$ at future $Z$ factories

Abstract: We investigate the prospects for detecting axion-like particles (ALPs, dubbed as "a") via the decay $Z\rightarrow a f\bar{f}$ at future $Z$ factories. Considering the decay channels $a\rightarrow \mu^+ \mu^-$ and $a\rightarrow b \bar{b}$ , four types of signals $\mu^+ \mu^- /E$, $b b /E$, $e^+ e^- \mu^+ \mu^-$ and $e^+ e^- b b$ are explored. We demonstrate that these channels are promising for detecting ALPs at $Z$ factories and obtain the sensitivity bounds on the couplings $g_{aZZ}$ and $g_{a\gamma Z}$.