In 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 gone through the entire set of data 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, each with 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 finding "strongly indicates that it is a Higgs boson," it said.
The discovery would be a strong contender for the Nobel Prize, though for whom remains unclear.