Probing anomalous $t\bar t Z$ interactions with rare meson decays
  Anomalous couplings of the $Z$ boson to top quarks are only marginally constrained by direct searches and are still sensitive to new particle dynamics at the TeV scale. Employing an effective field theory approach we consider the dimension-six operators which generate deviations from the standard-model vector and axial-vector interactions. We show that rare $B$ and $K$ meson decays together with electroweak precision observables provide strong constraints on these couplings. We also consider constraints from t-channel single-top production. 
Joachim Brod, Admir Greljo, Emmanuel Stamou and Patipan Uttayarat
hep-ph