GENEVA (AP) -- The search is all but over for a subatomic particle that is a crucial building block of the universe.
Physicists announced Thursday they believe they have discovered the subatomic particle predicted nearly a half-century ago, which will go a long way toward explaining what gives electrons and all matter in the universe size and shape.
The elusive particle, called a Higgs boson, was predicted in 1964 to help fill in our understanding of the creation of the universe, which many theorize occurred in a massive explosion known as the Big Bang. The particle was named for Peter Higgs, one of the physicists who proposed its existence, but it later became popularly known as the "God particle."
Last July, scientists at CERN, the Geneva-based European Organization for Nuclear Research, announced finding a particle they described as Higgs-like, but they stopped short of saying conclusively that it was the same particle or some version of it.
Scientists have now finished going through the entire set of data year and announced the results in a statement and at a physics conference in the Italian Alps.
"To me it is clear that we are dealing with a Higgs boson, though we still have a long way to go to know what kind of Higgs boson it is," said Joe Incandela, a physicist who heads one of the two main teams at CERN that each involve about 3,000 scientists.
Its existence helps confirm the theory that objects gain their size and shape when particles interact in an energy field with a key particle, the Higgs boson. The more they attract, the theory goes, the bigger their mass will be.
But, it remains an "open question," CERN said in a statement, whether this is the Higgs boson that was expected in the original formulation, or possibly the lightest of several predicted in some theories that go beyond that model.
But for now, it said, there can be little doubt that a Higgs boson does exist, in some form.
Whether or not it is a Higgs boson is demonstrated by how it interacts with other particles and its quantum properties, CERN said in the statement. The data "strongly indicates that it is a Higgs boson," it said.
The discovery would be a strong contender for the Nobel Prize, though it remains unclear whether that might go to Higgs and the others who first proposed the theory or to the thousands of scientists who found it, or to all of them.
The hunt for the Higgs entailed the use of CERN's atom smasher, the Large Hadron Collider, which cost some $10 billion to build and run in a 17-mile (27-kilometer) tunnel beneath the Swiss-French border.
It has been creating high-energy collisions to smash protons and then study the collisions and determine how subatomic particles acquire mass - without which the particles would fail to stick together.
Next page: A closer look at the Higgs boson
WHAT EXACTLY IS THE GOD PARTICLE?
Everything is made of atoms, inside of which are electrons, protons and neutrons. And those, in turn, are made of quarks and other subatomic particles. Scientists have wondered how these tiny building blocks of the universe acquire mass. Without mass, the particles wouldn't hold together - and there would be no matter.
One theory proposed by British physicist Peter Higgs and teams in Belgium and the United States nearly a half-century ago is that a new particle must be creating a "sticky" energy field that acts as a drag on other particles. The atom-smashing experiments have now confirmed that this particle exists in a form that is similar to - but perhaps not exactly like - what was proposed.
WHY DOES THIS MATTER?
The Higgs is part of many theoretical equations underpinning scientists' understanding of how the world came into being. If the particle didn't exist, then those theories would have needed to be fundamentally overhauled. The fact that it does exist, in some form, means scientists have been on the right track with their theories. So far the measurements seem to line up with was expected under the so-called Standard Model of particle physics. This is disappointing for scientists who were hoping to see new discoveries including a theory known as "super-symmetry" where particles don't just come in pairs - think matter and anti-matter - but quadruplets, all with slightly different characteristics.
HOW MUCH DID IT COST?
CERN's atom smasher, the Large Hadron Collider, which forms a 17-mile (27-kilometer) tunnel beneath the Swiss-French border, cost some $10 billion to build and run. This includes the salaries of thousands of scientists and support staff around the world who collaborated on the two experiments that independently pursued the Higgs.
WHAT IF ANY PRACTICAL RESULTS MIGHT COME FROM THE SEARCH?
None directly. But the massive scientific effort that led up to the discovery paid off in other ways, including the creation of the World Wide Web. CERN scientists developed it to make it easier to exchange information among each other. The vast computing power needed to crunch all of the data produced by the atom smasher also boosted the development of distributed - or cloud - computing, that is now entering mainstream services. Advances in solar energy capture, medical imaging and proton therapy - used in the fight against cancer - also resulted from the work of particle physicists at CERN and elsewhere.
WHAT COMES NEXT
It remains an open question, CERN says, whether this is exactly the Higgs boson of the Standard Model of particle physics, or possibly the lightest of several bosons predicted in some theories that go beyond the Standard Model. Finding the answer to this question will take time, as scientists keep probing the new particle until they fully understand how it works. And in doing so, they hope to understand the 96 percent of the universe that remains hidden from view. This may result in the discovery of new particles and even unknown forces of nature.
Jordans reported from Berlin.
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