Cifarelli was appointed full Professor at the University of Pisa in 1991. She moved to the University of Salerno in 1993. She works at CERN, the Laboratori Nazionali del Gran Sasso, DESY and the Istituto Nazionale di Fisica Nucleare. She has been involved in the design and construction of the ALICE experiment, which studies proton -proton and nucleus -nucleus collisions at extreme energies. She was made Head of the ALICE Data Analysis and Simulation Group in 2000. She served as Deputy Chairperson of the time of flight experiment at ALICE. She used the ALICE experiment to study quark-gluon interactions. She coordinates the Extreme Energy Events experiments, which uses muon detectors in high schools around Italy to study cosmic swarms. She serves on the DarkSide project; a 20 tonne Two-Phase LAr TPC for Direct Dark Matter Detection at the Laboratori Nazionali del Gran Sasso.