B -> Xs\gamma constraints on the top quark anomalous t-> c\gamma coupling

Observation of top quark flavor changing neutral process $t\to c+\gamma$ at the LHC would be the signal of physics beyond the Standard Model. If anomalous $t\to c\gamma$ coupling exists, it will affect the precisely measured $\mathcal{B}(\bar{B}\to X_s\gamma )$. In this paper, we study the effects of a dimension 5 anomalous $tc\gamma$ operator in $\bar{B}\to X_s\gamma$ decay to derive constraints on its possible strength. It is found that, for real anomalous $t\to c\gamma$ coupling ${\kappa }_{\mathrm{t}\mathrm{c}\mathrm{R}}^{\gamma }$, the constraints correspond to the upper bounds $\mathcal B (t \to c + \gamma)<6.54 \times 10^{-5}$(for$\kappa_{\rm{tcR}}^\gamma>0$)and$\mathcal B (t \to c + \gamma)<8.52 \times 10^{-5}$(for$\kappa_{\rm{tcR}}^\gamma<0$), respectively, which are about the same order as the $5\sigma$ discovery potential of ATLAS ($9.4\times {10}^{-5}$) and slightly lower than that of CMS ($4.1\times {10}^{-4}$) with $10{\mathrm{f}\mathrm{b}}^{-1}$ integrated luminosity operating at $\sqrt{s}=14$ TeV.