GENEVA -- Scientists believe the "God particle" that might explain the underpinnings of the universe is real, and they are about to present their evidence to the world.
Physicists at the world's biggest atom smasher plan to announce today that they have nearly confirmed the primary plank of a theory that could shape the scientific understanding of all matter.
The idea is much like gravity and Isaac Newton's discovery: It was there all the time before Mr. Newton explained it. But now scientists know what it is and can put that knowledge to further use.
The focus of the excitement is the Higgs boson, a subatomic particle that, if confirmed, could help explain why matter has mass, which combines with gravity to give an object weight.
Researchers at the European Organization for Nuclear Research say that they have compiled vast amounts of data that show the footprint and shadow of the particle -- all but proving it exists, even though it has never actually been glimpsed.
But two independent teams of physicists are cautious after decades of work and the outlay of billions of dollars.
They don't plan to use the word "discovery." They say they will come as close as possible to a "eureka" announcement without uttering a pronouncement as if from the scientific mountaintop.
"I agree that any reasonable outside observer would say, 'It looks like a discovery,' " said John Ellis, a British theoretical physicist who is a professor at King's College London and has worked at the research organization since the 1970s. "We've discovered something which is consistent with being a Higgs."
The research organization's atom smasher, the $10 billion Large Hadron Collider on the Swiss-French border, has been creating high-energy collisions of protons to investigate dark matter, anti-matter, and the creation of the universe, which many theorize occurred in a massive explosion known as the Big Bang. The phrase "God particle," coined by Nobel Prize-winning physicist Leon Lederman, is used by laymen, not physicists, more as an explanation for how the subatomic universe works than how it started.
Rob Roser, who leads the search for the Higgs boson at the Fermilab in Chicago, said: "Particle physicists have a very high standard for what it takes to be a discovery," and he thinks it is a hair's breadth away.
Mr. Roser compared the results that scientists will announce today to finding the fossilized imprint of a dinosaur.
Fermilab, whose competing atom smasher reported its final results Monday after shutting down last year, said its data don't settle the question of the Higgs boson, but it came tantalizingly close.
"It's a real cliffhanger," said Gregorio Bernardi, a physicist at the University of Paris who helped lead one of the main experiments at Fermilab. He cited "strong indications of the production and decay of Higgs bosons" in some of its researchers' observations.
Fermilab theorist Joseph Lykken said the Higgs boson "gets at the center, for some physicists, of why the universe is here in the first place."