  Experimentalists have long sought a method that allows them to control as
they like the branching ratios of an unstable particle decay and direct some
decay to follow one specific desired channel without another. The powerful
laser could make this dream come true. In this Letter and within the framework
of the standard electroweak model, we investigate theoretically the laser
effect on the branching ratios of different $Z$-boson decay modes by
calculating analytically the $Z$-boson decay into a pair of fermion-antifermion
$(Z\rightarrow f\bar{f})$ in the presence of a circularly polarized
electromagnetic field. It is found that, at high intensities, the $Z$-boson
could only decay invisibly into neutrinos, and its decay into any other pair of
charged fermions becomes impossible due to the increase in the effective mass
that fermions acquire inside the electromagnetic field. The influence of the
laser frequency and intensity on the lifetime is also included in order to
confirm the surprising result obtained for the pion lifetime in a previous
paper [ Mouslih S \textit{et al} 2020 \textit{Phys. Rev. D} \textbf{102} 073006
].
