Double Top Production at Hadronic Colliders

We calculate the contribution of anomalous top-quark interaction with a gluon, photon, and $Z$-boson (FCNC) to $t \bar t$ pair production in hadronic collisions. Using the current data from Run~1 of the Tevatron we evaluate the upper limit on the the anomalous coupling of $t$-quark with gluon, $|\kappa_g/\Lambda| \le 0.52$ TeV$^{-1}$. We examine the production of double top ($t t$ or $\bar t \bar t$) at hadronic colliders as a result of FCNC interactions of the top quark. It is shown that the study of such reactions at LHC collider makes possible to obtain the constraint on strength of coupling at the level of $|\kappa_g /\Lambda| \le 0.09$ TeV$^{-1}$.