Q&A: What is the Higgs Boson?

November 4, 2012

On July 4, 2012, scientists at the European Organization for Nuclear Research — the world’s largest particle physics laboratory, also known by its French acronym CERN — announced the discovery of a particle likely to be the long-sought-after Higgs boson. Putting aside the public hype of the Higgs as a “God particle,” what exactly does this discovery mean?

The Higgs is the last expected piece of a theory called the Standard Model, which essentially describes how the universe works on a subatomic scale. It is by the Standard Model, for example, that we can manipulate electrons precisely enough to see individual atoms through microscopes. In spite of all it can explain, however, the Standard Model has a missing piece.

The model predicts that electromagnetism and the weak force, which causes nuclei to decay, are really two sides of the same coin and that these forces are composed of counterpart particles: photons, and W and Z bosons. Because of the
analogous, correspondent nature of the two forces, scientists expected the W and Z bosons to be massless like the photon, but these particles were surprisingly found to have significant mass, leaving researchers puzzled by inconsistency.

The addition of the Higgs to the Standard Model accounts for the seemingly inexplicable mass of W and Z bosons: Higgs particles create a field or “fluid” (known as Higgs Condensate) through which all particles in existence continually travel. This field acts as a barrier to movement and thus varying degrees of resistance, depending on the properties of the particle in question, contribute to perceived mass. Some particles, like W and Z bosons, slow down in the Higgs field, while other particles, like photons, zip through it unaffected, massless and minute.

Although this model serves as a strong theory, the existence of the Higgs has been difficult to prove — until this summer’s discovery. While CERN researchers have yet to confirm the discovered particle’s identity indefinitely, it is very likely the missing piece in our physical understanding of the universe.

An artist’s approximation of a collision of two protons that produce a Higgs. Courtesy of CERN National Geographic.