After nearly five decades of research to confirm their theory, Francois Englert and Peter Higgs were awarded the Nobel Prize for physics on Tuesday for work that led to last year's discovery of the Higgs boson.
The Nobel Prize committee named the winners "for the theoretical discovery of a mechanism that contributed to the understanding of the origin of mass of subatomic particles," said Staffan Normark, permanent secretary of the Royal Swedish Academy of Sciences, at a news conference.
The Higgs boson is considered evidence of a pervasive field called the Higgs field that endows other particles with mass, one of the mysterious attributes of physics. It was the last to be discovered of the collection of fundamental particles predicted by what physicists call the Standard Model.
But it wasn't easy to find. It took thousands of scientists working at the a underground particle accelerator 27km in circumference called the Large Hadron Collider at CERN near Geneva, an effort that took years.
In 2011 CERN said the LHC had found a hint of the Higgs but stopped well short of declaring it to be verified. In 2012, the scientists declared the likelihood to be 99.99999 percent, then in 2013, increased that even more after gathering more data.
Higgs, from the University of Edinburgh in the UK, and Englert, from L'Université libre de Bruxelles in Belgium, laid out the case for the Higgs boson in independent papers in 1964. Englert collaborated with another physicist, Robert Brout, who died and therefore isn't eligible for the Nobel Prize, which is worth about $1.25 million.
The Higgs boson discovery doesn't mean physicists can pack up and go home, though. For one thing, there's the matter of which Higgs boson they discovered. There could be several, which would help fathom an idea that physicists call supersymmetry that predicts particles in the Standard Model have companions. Some of those companions could help explain dark matter, a form of matter that so far has only been detected by its gravitational influence.
Another shortcoming of the Standard Model is it predicts that other particles called neutrinos should be massless, but experiments starting in the 1990s showed that they had very small mass.
The LHC experiments, using two independent detectors called Atlas and CMS, fixed the Higgs boson mass at 125 giga electron volts (GeV), which is one hundred times the mass of the more ordinary proton particle. The LHC works by smashing protons together at extremely high speed, and the resulting energy release can be enough to produce new particles. The Higgs boson's heavy weight was one reason it was difficult to produce -- indeed the main reason to build the LHC was to find it.
New results are possible from CERN. The LHC is currently shut down for upgrades that are planned to double the energy level for its colliding protons.
Updated at 4:40 a.m. PT and 5:08 a.m. PT Added details beyond what appeared in the original post.