June 14, 1928|
New York City, New York, USA
|Died||May 3, 2011
|Institutions||Universite Libre de Bruxelles
|Alma mater||New York University(BS)
|Known for||quantum field theory
|Notable awards||Sakurai Prize
Wolf Prize in Physics
Robert Brout (June 14, 1928 – May 3, 2011) was a Belgian theoretical physicist who made significant contributions in elementary particle physics. He was a Professor of Physics at Université Libre de Bruxelles.
In 1964, Robert Brout, in collaboration with François Englert, discovered how mass can be generated for gauge particles in the presence of a local abelian and non-abelian gauge symmetry. This was demonstrated by them, both classically and quantum mechanically, successfully avoiding theorems initiated by J. Goldstone while indicating that the theory would be renormalizable. Similar ideas have been developed in condensed matter physics.
Peter Higgs and Gerald Guralnik, C. R. Hagen, and Tom Kibble came to the same conclusion as Brout and Englert. The three papers written on this boson discovery by Higgs, Brout and Englert, and Guralnik, Hagen, Kibble were each recognized as milestone papers by Physical Review Letters 50th anniversary celebration. While each of these famous papers took similar approaches, the contributions and differences between the 1964 PRL symmetry breaking papers is noteworthy. This work showed that the particles that carry the weak force acquire their mass through interactions with an all-pervasive field that is now known as the Higgs field, and that the interactions occur via particles that are widely known as Higgs bosons. As yet, these Higgs bosons had not been observed experimentally; however, most physicists believed that they exist. On July 4, 2012, it was announced at CERN that a new particle, "consistent with a Higgs boson", had been discovered with 5 sigma confidence in the mass region around 125-126 GeV. 
In 1971, Gerardus 't Hooft, who was completing his PhD under the supervision of Martinus J. G. Veltman at Utrecht University, renormalized Yang-Mills theory in accordance with Veltman's suggestion that this was possible. They showed that if the symmetries of Yang-Mills theory were to be broken according to the method suggested by Robert Brout, Francois Englert, Peter W. Higgs, Gerald Guralnik, C. R. Hagen and Tom Kibble then Yang-Mills theory is indeed renormalizable. Renormalization of Yang-Mills theory is one of the biggest achievements of twentieth century physics. Gerardus 't Hooft and Martinus J. G. Veltman were awarded the Nobel Prize in Physics in 1999 for this work.
In addition to this work on elementary particle physics, in 1978, Brout, in collaboration with F. Englert and E. Gunzig, was awarded the first prize gravitational award essay  for their original proposal of cosmic inflation as the condition of the cosmos prior to the adiabatic expansion, (i.e. the conventional big bang), after cosmogenesis.
Dr. Brout was awarded the 2010 J. J. Sakurai Prize for Theoretical Particle Physics (with Guralnik, Hagen, Kibble, Higgs, and Englert) by The American Physical Society “For elucidation of the properties of spontaneous symmetry breaking in four-dimensional relativistic gauge theory and of the mechanism for the consistent generation of vector boson masses.”  In 2004, Robert Brout, Francois Englert, and Peter Higgs were awarded the Wolf Prize in Physics "for pioneering work that has led to the insight of mass generation, whenever a local gauge symmetry is realized asymmetrically in the world of sub-atomic particles".
- Biography of Robert Brout at Physicstoday.org
- Physical Review Letters - 50th Anniversary Milestone Papers
- Contributions of Robert Brout
- Wolf prize goes to particle theorists
- The Nobel Prize in Physics 1999
- Gravity Research Foundation Awards
- American Physical Society - J. J. Sakurai Prize Winners
- The Wolf Prize in Physics in 2004