The Brout-Englert-Higgs boson

François Englert
Professor Emeritus, Université Libre de Bruxelles, Brussels, Belgium, and Distinguished Visiting Professor in Residence, Chapman's Institute for Quantum Studies, Chapman University, Orange, CA USA
Peter W. Higgs
Professor Emeritus, University of Edinburgh, Scotland, United Kingdom

Englert and Higgs have been suggested as possible Nobel Prize winners “for their prediction of the Brout-Englert-Higgs boson”

In 1964 the theoretical physicists François Englert and Robert Brout of the Université Libre de Bruxelles and Peter Higgs at the University of Edinburgh independently proposed an answer to the question: what endows matter with mass? This weighty puzzle lies at the heart of the Standard Model of particle physics because the more massive a particle is, the shorter the range over which it can interact with other particles and forces.

A naïve version of particle physics theory predicts that the virtual particles or gauge bosons carrying the weak interaction should be massless. However, that is manifestly not the case: the W and Z bosons are about 100 times more massive than the proton, heavier even than atoms of iron.

It is not uncommon for a law of physics to break down if an assumption about symmetry or boundary conditions is not met. For example, Newtonian mechanics ceases to apply at velocities where relativistic effects become manifest. This consideration led physicists to realize that under certain conditions there could be a mechanism that blocked the operation of symmetry laws in particle physics.

Brout and Englert made the first move in August 1964, showing that bosons could be massive if an unusual kind of field permeated empty space, thereby breaking the governing symmetry for the electroweak interaction. Their brief paper showed that in the case of broken symmetry the field would not necessarily lead to massless particles. In October 1964 Higgs independently reached the same conclusion using a classical theory.

The Higgs mechanism is a theoretical model of the process by which elementary particles gain mass. They do so by interacting with the Higgs field that extends throughout space. In a footnote Higgs remarked that his conclusions about the masses of particles were conjectures. He predicted a new massive spin-zero boson.

The detection of that Brout-Englert-Higgs boson would show that the Standard Model is correct. However, almost four decades elapsed between the prediction and the tentative confirmation of detection by the Large Hadron Collider.

Commentary on the Physics Laureates by Simon Mitton, Physics correspondent, ScienceWatch. Dr. Mitton is currently Vice-President (2012–2014) of the Royal Astronomical Society.