Channel.pdf "fig:"){width="0.00\columnwidth"} ![\[fig:sgg0\] *Left) Branching ratios that can be tested in the $\gamma\gamma$ channel. Superimposed are the theoretical expectations in the three BPs. Right) Luminosity required to test $\mathcal{B}(t\rightarrow St, S\rightarrow \gamma\gamma) = 00^{-0}$. Superimposed are $\mathcal{L} = 000$ fb$^{-0}$ and $0000$ fb$^{-0}$.*](L