Top-Quark Decay Via the Anomalous Coupling $\bar t c \gamma$ at Hadron   Colliders
  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. 
T. Han, K. Whisnant, B.-L. Young and X. Zhang