"I think we have it," said Rolf Heuer, director general of CERN in Geneva, told The New York Times Wednesday in a telephone interview.
The discovery -- which also could be vital to understanding how the universe began -- is "a historic milestone," Heuer said.
"It's great to discover a new particle but you have find out what its properties are," said John Ellis, a theorist at CERN, the European Organization for Nuclear Research.
"If the boson really is not acting standard, then that will imply that there is more to the story -- more particles, maybe more forces around the corner," Neal Weiner, a New York University theorist, told the Times. "What that would be is anyone's guess at the moment."
Some physicists are calling the discovery a "Higgs-like" particle, the Times said, stopping short of saying it was Higgs boson, known as the "God particle," the final missing ingredient in the standard model of particle physics.
Under the standard model, which ruled physics for 40 years, the Higgs boson is the only visible demonstration of an invisible force field that pervades space and gives otherwise mass-less elementary particles mass, the Times said. Without the Higgs field, or something like it, physicists said there would be neither atoms nor life.
"This is a big moment for particle physics and a crossroads -- will this be the high water mark or will it be the first of many discoveries that point us toward solving the really big questions that we have posed?" Michael Turner, a University of Chicago cosmologist and chair of the physics center board, told the Times.