John Iliopoulos (Greek: Ιωάννης Ηλιόπουλος; 1940, Kalamata, Greece) is a Greek physicist and the first person to present the Standard Model of particle physics in a single report. He is best known for his prediction of the charm quark with Sheldon Lee Glashow and Luciano Maiani (the "GIM mechanism"). Iliopoulos is also known for demonstrating the cancelation of anomalies in the Standard model. He is further known for the Fayet-Iliopoulos D-term formula, which was introduced in 1974. He is currently an honorary member of Laboratory of theoretical physics of École Normale Supérieure, Paris.
Iliopoulos graduated from National Technical University of Athens (NTUA) in 1962 as a Mechanical-Electrical Engineer. He continued his studies in the field of Theoretical Physics in University of Paris, and in 1963 he obtained the D.E.A, in 1965 the Doctorat 3e Cycle, and in 1968 the Doctorat d' Etat titles. Between the years 1966 and 1968 he was a scholar at CERN, Geneva. From 1969 till 1971 he was a Research Associate in Harvard University. In 1971 he returned in Paris and began working at CNRS. He also held the director position of the Laboratory of Theoretical Physics of Ecole Normale Superieure between the years 1991-1995 and 1998-2002. In 2002, Iliopoulos was the first recipient of the Aristeio prize, which has been instituted to recognize Greeks who have made significant contributions towards furthering their chosen fields of science. Iliopoulos and Maiani were jointly awarded the 1987 Sakurai Prize for theoretical particle physics. In 2007 Iliopoulos and Maiani received the Dirac Medal of the ICTP "(f)or their work on the physics of the charm quark, a major contribution to the birth of the Standard Model, the modern theory of Elementary Particles."
- S. L. Glashow; J. Iliopoulos; L. Maiani (1970). "Weak Interactions with Lepton-Hadron Symmetry". Phys. Rev. D2 (7): 1285. Bibcode:1970PhRvD...2.1285G. doi:10.1103/PhysRevD.2.1285.
- Bouchiat, Cl, Iliopoulos, J, and Meyer, Ph (1972) . "An anomaly-free version of Weinberg's model." Physics Letters B38, no. 7 (1972) 519-523.