François Englert (left) and Peter Higgs at CERN on July 4, 2012, on the occasion of the announcement of the discovery of a Higgs boson by the ATLAS and CMS experiments. // Maximilien Brice/CERN
Sometimes it takes five decades to prove a theory as fact.
That’s what happened in 2012 when the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) confirmed the discovery of the Higgs boson. And then this week, the Royal Swedish Academy of Sciences awarded the Nobel Prize in physics to Peter Higgs and François Englert
“for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle.”
So, where did the idea of the Higgs boson come from? Scientists in the 1960s and early 1970s had worked up a theory that describes all ordinary matter (like stars, planets, and people) and the forces that govern it. This “standard model” of particle physics, however, couldn’t explain how each particle gets its mass.
In 1964, Higgs and Englert independently hypothesized a field filling the universe that some particles interact with. Those that interact with this Higgs field, like an electron, have mass; those that ignore it, like a photon, have no mass. This field also has a force-carrier particle, called the Higgs boson. (A more familiar force-carrier particle is the photon, which is part of the electromagnetic field.) But while scientists had a descriptive theory of the Higgs field and its Higgs boson, they had never detected that boson — so they didn’t have definitive proof that such a field exists.
Enter the LHC. The laboratory accelerates beams of protons to 99.9999991 percent of light-speed, and huge instruments monitor what happens when those protons collide. After crunching data at two of the LHC’s detectors — A Toroidal LHC Apparatus (ATLAS) and the Compact Muon Solenoid (CMS) — scientists announced July 4, 2012
, that they detected a particle with properties awfully similar to those of the predicted Higgs boson. A few more months later, they confirmed that the particle they saw was in fact the long-awaited Higgs boson. That detection meant that a Higgs field does in fact exist and made Higgs and Englert worthy recipients of the Nobel Prize.
To learn more about the Higgs discover and its important, check out the article then-Associate Editor Bill Andrews wrote for our November 2012 issue, “Why you should care about the Higgs boson!