Jonathan Richard Ellis (born July 1, 1946) is a
BritishThe United Kingdom of Great Britain and Northern Ireland is a sovereign state located off the northwestern coast of continental Europe. It is an island country, spanning an archipelago including Great Britain, the northeastern part of Ireland, and many small islands...
theoretical physicistTheoretical physics is a branch of physics which employs mathematical models and abstractions of physics in an attempt to explain natural phenomena. Its central core is mathematical physics,[Sometimes mathematical physics and theoretical physics are used synonymously to refer to the...]
. After completing his secondary education at
Highgate SchoolSir Roger Cholmeley's School at Highgate is a British independent school in Highgate, London, England. It is a member of both the Headmaster's Conference and the Eton Group. Highgate recently made the move towards co-education ending over 400 years of single sex education...
, he attended
Cambridge UniversityThe University of Cambridge , located in the City of Cambridge, Cambridgeshire, United Kingdom, is the second oldest university in the English-speaking world and the fourth oldest in Europe...
, earning his Ph.D. in theoretical (high-energy) particle physics in 1971. After brief post-doc positions at SLAC and Caltech, he went to
CERNThe European Organization for Nuclear Research , known as CERN , , is the world's largest particle physics laboratory, situated in the northwest suburbs of Geneva on the Franco–Swiss border, established in 1954...
and has held an indefinite (i.e., permanent) contract there since 1978. He was awarded the
Maxwell MedalThe Maxwell Medal and Prize is one of the principal awards made annually by the Institute of Physics. The award is made for outstanding contributions to theoretical physics and is intended to recognize theoretical physicists early in their careers....
and the Paul Dirac Prize by the
Institute of PhysicsThe Institute of Physics is a scientific charity devoted to increasing the practice, understanding and application of physics,and is the UK and Ireland's main professional body for physicists...
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 SouthamptonThe University of Southampton is a British public university located in the city of Southampton, England. The origins of the university can be dated back to the founding of the Hartley Institution in 1862 by Henry Robertson Hartley. In 1902 the Institution developed into the Hartley University...
, and twice won the First Award in the
Gravity Research FoundationThe Gravity Research Foundation, established in 1948 by businessman Roger Babson , was an organization designed to find ways to implement gravitational shielding...
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
CLICThe Compact Linear Collider is a proposed linear particle accelerator under design at CERN. It would be built after the Large Hadron Collider. CLIC is separate from the International Linear Collider project, and differs in its use of more novel technology to achieve a higher planned energy of...
(Compact Linear Collider) Steering Committee.
Scientific Research
Ellis' research interests focus on the phenomenological aspects of particle physics, though he has also made important contributions to astrophysics, 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 centered on the phenomenology of gauge theories. Working with
Dimitri NanopoulosDimitri Nanopoulos is a Greek physicist. He is one of the most regularly cited researchers in the world, cited more than 33,000 times over across a number of separate branches of science....
and Mary Gaillard, he proposed in 1976 the so-called
Higgs-strahlung process in which a
Higgs bosonThe Higgs boson is a massive scalar elementary particle predicted to exist by the Standard Model in particle physics. At present there are no known fundamental scalar particles in nature....
is radiated from a
Z-boson
(this proved to be the best way to search for the Higgs boson at LEP), 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 Na48 experiments at CERN). Also in 1976, he published two papers suggesting techniques for finding the
gluonGluons are elementary expressions of quark interaction, and are indirectly involved with the binding of protons and neutrons together in atomic nuclei...
in e+e- annihilations. The following year he predicted the mass of the
bottom quarkThe bottom quark is a third-generation quark with a charge of − e. Although all quarks are described in a similar way by the quantum chromodynamics, the bottom quark's large mass , a bit more than four times the mass of a proton), combined with low values of the CKM matrix elements...
on the basis of Grand Unified Theory, before this quark was observed in experiment. In 1978 he published a frequently cited general paper on such theories, with Andrzej J. Buras, Gaillard and Nanopoulos.
In the 1980s, Ellis became a leading advocate of models of
SupersymmetryIn particle physics, supersymmetry is a symmetry that relates elementary particles of one spin to other particles that differ by half a unit of spin and are known as superpartners...
. In one of his earliest works, he showed that the lightest supersymmetric particle is a natural
Dark MatterIn astronomy and cosmology, dark matter is hypothetical matter that is undetectable by its emitted radiation, but whose presence can be inferred from gravitational effects on visible matter...
candidate. In 1991, he showed that radiative corrections to the mass of the lightest
Higgs bosonThe Higgs boson is a massive scalar elementary particle predicted to exist by the Standard Model in particle physics. At present there are no known fundamental scalar particles in nature....
in minimal supersymmetric models increased that mass beyond the reach of the LEP searches. The search for the Higgs boson remains one of the most important topics in particle physics, motivating researchers at both the
FermilabFermi National Accelerator Laboratory , located in Batavia near Chicago, Illinois, is a U.S. Department of Energy national laboratory specializing in high-energy particle physics. As of January 1, 2007, Fermilab is operated by the Fermi Research Alliance, a joint venture of the University of...
TevatronTevatron is a circular particle accelerator at the Fermi National Accelerator Laboratory in Batavia, Illinois and remains the highest energy particle collider in the world until collisions begin at the Large Hadron Collider . The Tevatron is a synchrotron that accelerates protons and antiprotons in...
and at the
CERNThe European Organization for Nuclear Research , known as CERN , , is the world's largest particle physics laboratory, situated in the northwest suburbs of Geneva on the Franco–Swiss border, established in 1954...
LHCLHC may refer to:* Large Hadron Collider, a particle accelerator and collider located on the Franco-Swiss border near Geneva, SwitzerlandLHC also may refer to:* La hora Chanante, a Spanish comedy television show...
. More generally, Ellis and collaborators pioneered the analysis of so-called
benchmark scenarios meant to illustrate the range of phenomenology to be expected from supersymmetric models; such analyses have played a major role in evaluating the promise of various future accelerator options.
In parallel to his investigations of supersymmetric phenomenology, Ellis has also advocated phenomenological probes of
quantum gravityQuantum gravity is the field of theoretical physics attempting to unify quantum mechanics with general relativity in a self-consistent manner, or more precisely, to formulate a self-consistent theory which reduces to ordinary quantum mechanics in the limit of weak gravity and which reduces to...
and
string theoryString theory is a developing branch of theoretical physics that combines quantum mechanics and general relativity into a quantum theory of gravity...
. These probes include direct tests of quantum mechanics with the CPLEAR Collaboration and the derivation of Grand Unified Theories from string theory. In this vein, his work on tests of the constancy of the velocity of light and models of string cosmology received separate prizes from the
Gravity Research FoundationThe Gravity Research Foundation, established in 1948 by businessman Roger Babson , was an organization designed to find ways to implement gravitational shielding...
.
An impression of the impact of Ellis' research can be obtained from the
SPIRESSpires is the name of:* SPIRES, a database for publications in High-Energy Physics* Speyer , a city in Germany* The Spires, a commercial conference centre, operated out of Church House, Belfast by the Presbyterian Church in Ireland...
reference system for scientific papers in particle physics and related fields. As of 2008, this data base lists over 850 scientific papers of which he is an author; altogether the sum of citations is above 40,000. In 2004 a SPIRES survey ranked him as the second most-cited theoretical physicist. His publications include one paper with over 1000 citations, six more with over 500 citations, and 104 other papers with at least 100 citations each.
Support of Particle Accelerator Projects
In addition to his theoretical research, John Ellis has been an advocate and supporter of future accelerators, beginning with LEP and the
LHCLHC may refer to:* Large Hadron Collider, a particle accelerator and collider located on the Franco-Swiss border near Geneva, SwitzerlandLHC also may refer to:* La hora Chanante, a Spanish comedy television show...
, and extending to
CLICThe Compact Linear Collider is a proposed linear particle accelerator under design at CERN. It would be built after the Large Hadron Collider. CLIC is separate from the International Linear Collider project, and differs in its use of more novel technology to achieve a higher planned energy of...
, photon colliders, and future proton accelerators. Naturally his theoretical work reflected these connections, as when he showed that data from the
SLCSLC may refer to, among other things:* Salt Lake City, Utah**Salt Lake City International Airport, IATA Airport Code**SLC Punk!, a film set in Salt Lake City* Salt Lake County, Utah* Sounds Like Chicken, a music group* South Lanarkshire Council...
and from LEP could be used to predict the masses of the top quark and the Higgs boson. Such predictions are now a main stream activity within particle physics, and constitute one of the most important bridges between the experimental and theoretical communities.
Concerning the
LHCLHC may refer to:* Large Hadron Collider, a particle accelerator and collider located on the Franco-Swiss border near Geneva, SwitzerlandLHC also may refer to:* La hora Chanante, a Spanish comedy television show...
, Ellis played a leading role in the seminal 1984 workshop on physics to be done with such an accelerator. Since then he has written many articles on searches for Higgs bosons and supersymmetric particles at the LHC, both for the pariticle physics community and at a more popular level. His most recent LHC physics review appeared in a Nature Insight supplement on July 19, 2007.
John Ellis has been a strong supporter of the
CLICThe Compact Linear Collider is a proposed linear particle accelerator under design at CERN. It would be built after the Large Hadron Collider. CLIC is separate from the International Linear Collider project, and differs in its use of more novel technology to achieve a higher planned energy of...
option for a future high-energy e+e- linear collider; this option is pursued most strongly at CERN. He was convenor of the CLIC Physics Study Group the produced the main report on this option, in 2004.
Outreach and Spreading Physics around the World
Ellis is frequently invited to give public lectures on particle physics and related topics. For example, in the two-year period 2004-5, he gave public lectures in Geneva (in French), in Granada and Barcelona (in Spanish), in Rome (in Italian) and in Warsaw (in English).
While at CERN he often gives introductory talks to visitors, ranging from official delegations from the United Kingdom to physics teachers at the high-school level.
Ellis is well known for his efforts to involve non-European nations in CERN scientific activities. In the context of the LHC, he has interacted frequently with physicists, administrators at universities and institutes and ministers of funding agencies and diplomatic corps from a wide variety of countries, ranging from major CERN partners like the United States, Russia, Japan, Canada, India, Israel and China, to states with nascent physics programs such as Azerbaijan, the Baltic republics, Bolivia, Colombia, Croatia, Cyprus, Iran, Madagascar, New Zealand, Pakistan, Romanie, Sri Lanka, Vietnam, and lately in Palestine, and many others. These interactions have fostered the international character of CERN and opened the pathways of scientific discourse all around the world.
External links