"The results are particularly important because they use a completely different and complementary way of searching for the Higgs boson. This gives us more confidence that what we are seeing is really evidence of new physics rather than just a statistical fluke," Tovey added.
Tovey said scientists will have to wait until Wednesday for the latest results from the European scientists before "getting the full picture" concerning the Higgs boson.
CERN spokesman James Gillies called Fermilab's findings "a nice result," but added that "it will be interesting to see how it lines up with CERN's results on Wednesday. Nature is the final arbiter so we'll have to be a little more patient before we know for sure whether we've found the Higgs."
Tom LeCompte, a scientist at the Department of Energy's Argonne National Laboratory in Illinois who works at CERN and knows the results, said he was confident the Higgs would be shown to exist, or not exist, this year. But he would not say if the findings to be unveiled Wednesday would be definitive.
"I know 2012 is the year. I can't tell you July is the month," LeCompte said.
Others were less cautious. "This is the most exciting week in physics history," said theoretical physicist Joe Lykken of Fermilab.
The Higgs particle is the final quarry in a hunt that began some 40 years ago, when physicists assembled what is now known as the Standard Model. The model is considered the culmination of a quest for the fundamental constituents of matter and the forces that determine how they interact, a search that began some 2,400 years ago with Greek philosopher Democritus' hypothesis that everything is composed of indivisible atoms.
According to the Standard Model, matter is composed of various combinations of six leptons, including the well-known electron and the ghostly neutrino, and six quarks, to which physicists have given whimsical names such as "charm," "bottom," and "strange." The protons at the core of atoms, for instance, are composed of two "up" quarks and one "down" quark.