Study of Top Quark FCNC

Abstract

The potential of the LHC for investigation of anomalous top quark interactions with gluon (tug, tcg) through the production of tW-channel of single top quark is studied. In the Standard Model, the single top quarks in the tW-channel mode are charge symmetric meaning that σ(pp → t + W −) = σ(pp → ¯ t + W +). However, the presence of anomalous FCNC couplings leads to charge asymmetry. In this paper a method is proposed in which this charge asymmetry may be used to constrain anomalous FCNC couplings. The strength of resulting constraints is estimated for the LHC for the center of mass energies of 7 and 14 TeV.

Probing the anomalous tqgamma couplings in photon-proton collisions

“…Top quark interactions play a key role and provide very unique exploration opportunities to extended theories due to their huge mass nearly the same amount with the electroweak scale, for the examination of these theories. [3] A salient feature of the usual top quark sector is that the Flavor Changing Neutral Current (FCNC) transitions are exceedingly weak as a result of the Glashow-Iliopoulos-Maiani (GIM) mechanism. According to the GIM mechanism, these interactions are prohibited at tree-level and are immensely repressed at the loop-level.…”

Probing the anomaloustqγ couplings through single top production at the future lepton–hadron colliders

“…In order to answer these questions, different theoretical models beyond the SM, called new physics (NP), have been suggested in the literature. In addition, the interactions of the top quark take more attention among these NP model interactions, because the top quark is the only fermion that it has mass at the scale of electroweak symmetry breaking [3].…”