The American research institute had previously claimed it was moving ahead of its European rival in the race to discover one of the biggest prizes in physics, the elusive Higgs Boson particle.
Fermilab reported that its researchers have managed to shrink the territory where they expect the so-called “God Particle” to be found.
British physicist Peter Higgs set out to answer the question that baffled physicists: how do particles acquire mass?
In 1964, he came up with the idea that a background field must exist that would act like treacle, meaning particles passing through it would acquire mass by being dragged through a mediator, which theoreticians dubbed the Higgs Boson.
The Higgs became known as the "God Particle" because it is everywhere but remains frustratingly elusive.
Finding confirmation of the Higgs would answer many questions about the so-called Standard Model, the theory that summarizes our present knowledge of particles
. Scientists throughout the years have narrowed down the ranges of mass that the Higgs is likely to have.
European physicists are also searching for the Higgs, amongst other things, with the Big Bang atom-smasher, the Large Hadron Collider.
However, the LHC suffered a months-long setback after being switched on in September 2008 at the European Organization for Nuclear Research (CERN) below the Franco-Swiss border.
Researchers at the rival Fermilab have increased efforts to discover the Higgs before the LHC is back on track in September of this year.
Femilab said in a press release that researchers at CERN had already determined that the Higgs must weigh more than 114 GeV/c2. Calculations of quantum effects involving the Higgs Boson require its mass to be less than 185 GeV/c2.
Physicists at CERN were able to carve out a section in the middle of that range using Fermilab's Tevatron collider, establishing that the particle it cannot have a mass in between 160 and 170 GeV/c2.
Two major research groups have analyzed three inverse femtobarns of collision data, the scientific unit that scientists use to count the number of collisions. They say that each experiment expects to receive a total of about 10 inverse femtobarns by the end of 2010.
Fermilab researcher Rob Roser said a particle collision at the Tevatron collider can produce a Higgs boson in many different ways, and the Higgs particle can then decay into various particles.
"Each experiment examines more and more possibilities. Combining all of them, we hope to see a first hint of the Higgs particle."