Flavor-Changing Top Quark Rare Decays in the Littlest Higgs Model with T-Parity

Abstract

We analyze the rare and flavor changing decay of the top quark into a charm quark and a gauge boson in the littlest Higgs model with T-parity (LHT). We calculate the one-loop level contributions from the T-parity odd mirror quarks and gauge bosons. We find that the decay $t\to cV,(V=g,\gamma ,Z)$ in the LHT model can be significantly enhanced relative to those in the Standard Model. Our numerical results show that the top quark FCNC decay can be as large as $Br(t\to cg)\sim 10^{-2}$, $Br(t\to cZ)\sim 10^{-5}$ and $Br(t\to c\gamma )\sim 10^{-7}$ in the favorite parameter space in the LHT model.

Comments: 12 pages, 3 figures