  We determine the constraints on the anomalous top-quark coupling associated
with the flavor-changing neutral current vertex $\bar t c \gamma $ from the
limits on the $b$-quark rare decay $b\rightarrow s \gamma$ and non-standard
top-quark decays. Based on these constraints, we discuss the experimental
observability of the rare decay mode $t \rightarrow c \gamma$, both at the
Fermilab Tevatron with a luminosity-upgrade and at the LHC.

High Energy Physics - Phenomenology