The scientist who heads the world's largest particle physics laboratory said he thinks it is "beyond any doubt" that a Higgs boson particle has been discovered.
Professor Rolf Heuer, director general of Cern, the European Organisation for Nuclear Research, said he would "stick his neck out" and say it had been found by scientists.
He was speaking during a visit to Edinburgh where he met Professor Peter Higgs, the man who gave his name to the particle.
Prof Heuer was delivering a lecture to students, academics and members of the public at Heriot-Watt University.
He discussed the announcement made in July that teams at the Large Hadron Collider (LHC), the £2.6 billion "Big Bang" atom-smasher near Geneva, Switzerland, had found a new particle "consistent" with the Higgs boson.
Of the discovery, he said: "We have set a certain limit which the data significance has to exceed in order to call it a discovery. That limit we have reached on July 4, so I was very happy to state I think we have it, and I think we have it still.
"When they finalised the data, the significance has even increased, so this is why I stick my neck out and say I think it is beyond any doubt because it looks very, very clear and very well in hand, so I think we have found this new particle."
Prof Higgs, 83, the retired British physicist from Edinburgh University, hit on the concept of the Higgs mechanism in 1964 while walking in the Cairngorms. The Higgs boson gives matter mass and holds the physical fabric of the universe together.
Observations so far show the discovery looks and acts like the long-sought particle that has eluded them for 50 years.
Speaking before the lecture, Prof Higgs said: "The seminar on July 4 was an overwhelming experience for me, the end of a long road. Since then I have had an immense number of letters and emails, I get stopped in the street and asked for my autograph. It's been getting more and more hectic."