 Since then he has worked as a CNEN and INFN researcher at the Frascati National Laboratories; as a CNRS Visiting Scientist at the Laboratoire de Physique Théorique, École Normale Supérieure, Paris, and at the Theory Division at CERN, Geneva.In 1980 he was nominated Full Professor of theoretical physics in Italy.He became a staff member of the Theory Division at CERN in 1981.