Top quark FCNC decays and productions at LHC in littlest Higgs model with T-parity

Abstract

In the littlest Higgs model with T-parity (LHT) the newly introduced mirror quarks have flavor-changing couplings with the Standard Model (SM) quarks and may enhance the flavor-changing neutral-current (FCNC) top quark interactions which are extremely suppressed in the SM. In this work we perform a comprehensive study for the contributions of these mirror fermions to various top quark FCNC decays and productions at the LHC, which includes the decays t-> c V (V=g, \gamma, Z), t -> cgg and the productions proceeding through the parton processes cg -> t, gg -> t c_bar, cg -> tg, cg -> t\gamma and cg -> t Z. We find that although these FCNC processes can be greatly enhanced by the LHT contributions, they are hardly accessible at the LHC. Therefore, the LHT model may not cause the FCNC problem in the top quark sector if the top quark property is proved to be SM-like at the LHC.