New physics in top pair production

We present the latest results about searches for new physics in top quark pair production. The ATLAS and CMS collaborations results using data collected at LHC in 2012 at the energy of interactions of 8 TeV are included. Most of such searches look for vector-like quarks. No presence of excess is found and the 95% C.L. lower limits on vector-like quark masses are set between about $600 - 850\ \rm{GeV/c^2}$ depending on quark type and its decay mode. Searches for an excited top quark and for a baryon number violation in tt process are also presented.