In a seeming paradox, the mass of the top quark is nearly 200 times that of a proton. As a result scientists have likened this experiment to smashing together two tennis balls and finding a bowling ball in their place.

The increase in mass, however, is consistent with Einstein's theory that extra energy from high-speed particles can be translated into matter.

Margin of Error

Scientists were reluctant to call the results a conclusive discovery although there is only a.25 percent chance that the data was caused by non-top quark phenomena.

"A quarter of a percent is huge in the world of physics," said Franklin, who has been working on the project for 12 years.

The findings allow physicists to embrace a whole range of new initiatives including the calculation of the mass of another theoretical particle, the Higgs boson, said Franklin.

The mass of the boson is vitally important for physicists to develop a grand unifying theory linking together the four fundamental forces of nature: strong weak, gravitational and electromagnetic.

"Because the top [quark] is so massive, in a sense it's like a keystone in a bridge," Huth said. "When you find this keystone and put it in, the whole structure all of a sudden becomes apparent. That gives you a window to do the new interesting pieces of physics which you couldn't have really understood without the top."