Unparticle effects on top quark rare decays

Abstract

In this work we study the flavor changing neutral current(FCNC) decays of the top quark, $t\to c\gamma$ and $t\to cg$. The Standard Model, predictions for the branching ratios of these decays are about $\sim 5\times 10^{-14}$, and $\sim 1\times 10^{-12}$, respectively. The recent study presented by the ATLAS Collaboration gives a sensitivity on these branching ratios about $\sim 10^{-5}$ at C.L. The parameter space of $\lambda$, $\Lambda$, and $d$ where the branching ratios of $t\to c\gamma$ and $t\to cg$ decays exceed these predictions is obtained.