A Cern spokesman, while confirming the authenticity of the note, cautioned it has not been subject to rigorous scientific examination and could end up a false alarm.

"It's genuine, but what it comes from is a note written by a very small group of people in a large collaboration," James Gillies, director of communications at Cern, told BBC News.

"If those notes survive scrutiny, which is often not the case ... then the next stage in the peer review process is for them to go out to the collaboration as a whole.

"What was leaked was the first stage in that process ... at this stage we can't take it seriously and these things do come and go quite often."

In decades of attempts, no one has been able to detect the Higgs boson, central to the widely accepted theory of physics known as the Standard Model and thought to explain why all other particles have mass.