FCNC Top Quark Decays And Productions At LHC In TC2 Model

In the past decades, the remarkable agreement of experiment with theory testifies the correctness of the Standard Model (SM) in describing the electroweak physics. However, the theoretical defects of the SM itself suggest the existence of new physics. In general, new physics may significantly affect electroweak observables. Studying such effects to probe new physics is the main goal of this thesis.As the heaviest fermion in the Standard Model (SM), the top quark may be a sensitive probe of new physics. So far there remain plenty of room for new physics in top quark sector due to the small statistics of the top quark events at the Fermilab Tevatron colMder.Since the upcoming Large Hadron Collider (LHC) at CERN will produce top quarks copiously and allow to scrutinize the top quark nature, the new physics related to the top quark will be either uncovered or stringently constrained.The topcolor-assisted technicolor (TC2) model combines technicolor interaction with topcolor interaction, with the former being responsible for electroweak symmetry breaking and the latter for generating large top quark mass.The TC2 predicts a number of neutral scalar bosons like the top-pions and top-Higgs at the weak scale [?]. These scalars have flavor-changing neutral-current(FCNC) top couplings at tree-level, among which the top-charm FCNC couplings are most significant. We studied the top-quark productions at LHC in TC2,single top production associated with a neutral scalar at LHC in TC2 and top quark FCNC decay in TC2.