{\mathcal B}(t\bar{t} \rightarrow \colorbox{red}{\bf \color[rgb]{0,1,0} W b Z c}) = 
\frac{ N_\mathrm{candidates} - N_\mathrm{background} }
{{\mathcal A} \cdot \int {\mathcal L} dt \cdot \sigma_{t \bar{t}}}