Robert Brout (/braʊt/; June 14, 1928 – May 3, 2011) was an American-born Belgian theoretical physicist who made contributions in elementary particle physics.

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.

[5][6] 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.

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.

"[10] In 2004, Robert Brout, François 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".