Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a tiny fraction of a second early.
The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.
In the meantime, the group says it is being very cautious about its claims.
"We tried to find all possible explanations for this," said report author Antonio Ereditato of the Opera collaboration.
"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.
"When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"
Thursday, September 22, 2011
BREAKING: Possible Neutrinos moving at superluminal speeds at CERN!
When I was a kid and was bored in Chem classes I would occasionally daydream of a messenger arriving at the classroom door to tell the late, great, Fr Farrell of a scientific breakthrough.
Of course, in later years, I always assumed that it would be years before a breakthrough would filter down to High School Chem.
But, today, may be a possible day like that.
One to keep an eye on.
Ole Albert must be peering over the balcony to see what we are going to do. Isaac, standing next to him is taking the bets. END