Muonic Dark Boson Search at the BABAR Experiment

We report searches for a muonic dark boson coupling only to the second and third lepton families. The existence of the dark boson is probed in e$+$e- events using the full data sample collected by the BABAR experiment. No significant signal is observed. We set a limit on dark-sector coupling parameter, leading to improvements in the current bounds and further constrain the allowed parameter space.