(Reuters) - The physicists who theorized the existence of a basic subatomic particle half a century ago are confident recent data is proving they were right all along.

Peter Higgs, whose eponymous "Higgs boson" is the long-sought target of the $10 billion Large Hadron collider in Switzerland, told reporters on Tuesday he was sure a particle detected last July was one he had predicted in 1964.

"I think it will turn out to be (the Higgs boson), but it's just a question of getting out the additional information."

Data so far from CERN's LHC particle accelerator seemed unlikely to reveal a more exotic set of particles, Higgs said, and "fit too well" with a single particle that gives mass to matter envisaged by the Standard Model of physics.

"As far as I can see from the results now it's not yet totally confirmed, but it's practically sure - I'm ready to bet on it," Belgian physicist Francois Englert, who also theorized the particle, said before giving a speech to the European Parliament in Brussels.

Although the scientists predicted the presence of the particle years earlier, it took a multinational effort of over 100 countries to build the LHC, which two years into its operation yielded a result.

Higgs said that this type of collaborative research helped not only science, but the economy as a whole, and he was worried about proposed cuts to European Union science funding.

"What you do by cutting the science budget is to reduce your supply of young trained scientists who will do other things which are obviously more useful for your economy," he said.

"You may be cutting down on things which will provide a stimulus for your economy in the not too distant future."

For Higgs, who at 83 has retired from active research, the sudden attention brought on by the LHC discovery last July has been a little overwhelming.

"It has resulted in piles of piles of letters and emails on my floor at home," he said, explaining he had needed to enlist help from a team of colleagues just to sort through it.

The bashful professor has no hard feelings that he's not yet been tapped for the Nobel Prize in physics, saying he "was reprieved" and "got a stay of execution".

Touted by some as a possible winner in 2013, Higgs said that winning the Nobel for his work might leave the prize committee the unenviable task of having to choose between a number of co-discoverers, but he acknowledged he was in the running.

"As for what happens next year, I certainly feel vulnerable."

(Reporting by Ethan Bilby; Editing by Mark Heinrich)