ATLAS Experiment Sensitivity to the Flavor-Changing Neutral Currents Decay t--> Zq

The sensitivity of ATLAS experiment to the Branching ratio of the top-quark rare decay via flavor-changing neutral currents t-->Zq (where q represents the c and u quarks) has been studied at \sqrt{s}= 14 TeV in two decay modes: 1. the pure leptonic decay of gauge bosons: t\bar{t}-->(Wb)(Zq) with W-->lnu, Z-->l^{+}l^{-} 2. the leptonic decay of Z bosons and hadronic decay of W bosons: t\bar{t}-->(Wb)(Zq) with W-->jj, Z-->l^{+}l^{-} The dominant backgrounds Z+jets, W+Z and t\bar{t} has been analysed. The signal and backgrounds were generated via PYTHIA 5.7 and simulated using ATLFAST 2.14. Branching ratio for the leptonic and hadronic modes and combined results from both modes has been estimated at the 5\sigma level with an integrated luminosity of 10^{5} pb^{-1}.