Physicists say they are now confident they have discovered the long-sought Higgs boson

GENEVA - 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-kilometre) 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.