A LEAKED internal note from researchers at the world's largest atom-smasher has sparked speculation that the first evidence of an elusive subatomic particle called the Higgs boson has been found.
But physicists have urged caution, saying the results have not yet been verified and could be a false alarm.
One of the main scientific goals of the Large Hadron Collider, built deep underground near Geneva, has been to determine the existence or not of the mysterious boson.
Also known as the God particle because of its importance, it is a missing piece - the last of the many particles predicted to exist by the standard model of particle physics that has not yet been detected. It is thought to give all the other particles their mass.
Rumours of a possible sighting began to circulate when a note from four researchers analysing data from the ATLAS detector at the collider was posted anonymously on the internet.
The internal memo, reporting results from collisions that could be interpreted as a signature of the Higgs boson, was intended for the 3000 other scientists working on the project.
The note concluded: ''Exciting new physics, including new particles, may be expected to be found in the very near future.''
A spokesman for the Large Hadron Collider, James Gillies, confirmed the note was not a hoax, but said it was just an internal memo highlighting a possible interesting finding.
''It is way, way too early to say if there's anything in it or not. The vast majority of these notes get knocked down before they ever see the light of day,'' he told Wired Science.
Kevin Varvell, of the school of physics at the University of Sydney, said the finding had not yet been checked by other scientists in the ATLAS experiment. ''It is not an official result of the collaboration,'' he said.
The leak has angered some physicists.
''Very bad science to leak it. Many mistakes are made in unreviewed papers,'' Brian Cox, of the University of Manchester, said on Twitter.