Jonathan Richard Ellis (born 1 July 1946) is a British theoretical physicist who is currently Clerk Maxwell Professor of Theoretical Physics at King's College London. After completing his secondary education at Highgate School, he attended King's College, Cambridge, earning his PhD in theoretical (high-energy) particle physics in 1971. After brief post-doc positions in the SLAC Theory Group and Caltech, he went to CERN and has held an indefinite contract there since 1978. He was awarded the Maxwell Medal and the Paul Dirac Prize by the Institute of Physics in 1982 and 2005 respectively, and is an Elected Fellow of the Royal Society of London since 1985 and of the Institute of Physics since 1991. He was awarded an Honorary Doctorate from the University of Southampton, and twice won the First Award in the Gravity Research Foundation essay competition (in 1999 and 2005). He is also Honorary Doctor at Uppsala University. Ellis' activities at CERN are wide-ranging. He was twice Deputy Division Leader for the theory ("TH") division, and served as Division Leader for 1988–1994. He was a founding member of the LEPC and of the LHCC; currently he is chair of the committee to investigate physics opportunities for future proton accelerators, and is a member of the extended CLIC (Compact Linear Collider) Steering Committee. Ellis was appointed Commander of the Order of the British Empire (CBE) in the 2012 Birthday Honours for services to science and technology. Scientific research Ellis' research interests focus on the phenomenological aspects of particle physics, though he has also made important contributions to astrophysics and cosmology and quantum gravity. Most of his publications relate directly to experiment, from interpreting measurements and the results of searches for new particles, to exploring the physics that could be done with future accelerators. He was one of the pioneers of research at the interface between particle physics and cosmology, which has since become a sub-specialty of its own: particle astrophysics. Ellis' early research accomplishments are centred on the phenomenology of gauge theories. Working with Dimitri Nanopoulos and Mary Gaillard, he proposed in 1976 the so-called "Higgs-strahlung" process in which a Higgs boson is radiated from a Z-boson (this proved to be the best way to search for the Higgs boson at the Large Electron–Positron Collider), and in the same year estimated the direct CP-violation contribution to rare neutral kaon decays (which led to the success of the NA31 and