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

Abstract

We investigate the prospects of detecting axion-like particles (ALPs, dubbed as "a") via the decay Z → af f at future Z factories. Considering the decay channels a → µ + µ − and a → b b , four types of signals µ + µ − / E, bb / E, e + e − µ + µ − and e + e − bb 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 aγZ .