FCNC TOP QUARK PRODUCTION AND DECAY AS ANALYZERS OF NEW PHYSICS

Motivated by the facts that the LHC will be, among other things, a top-quark factory and that the top is the quark closest to the onset of new physics, we have calculated FCNC single top production and rare decays of top. We present results for the SM (unrealistically small) and for MSSM (potentially large). Finally we consider lepton number violation in top decay, mediated by a heavy Majorana neutrino.