double team Higgs boson
Scientists from the CDF and DZero collaborations at DOE's Fermilab have combined Tevatron data from their two experiments to restrict the mass of the Higgs boson. Their results indicate that a mass for the Higgs of 170 GeV/c2 is excluded, with 95 percent probability (see graphs). This is the first time that the Tevatron experiments directly restrict the Higgs mass.
Joint CDF, DZero effort lands Fermilab in Higgs territory.
Batavia, Ill.--Scientists from the CDF and DZero collaborations at the U.S. Department of Energy's Fermilab have combined Tevatron data from the two experiments to advance the quest for the long-sought Higgs boson. Their results indicate that Fermilab researchers have for the first time excluded, with 95 percent probability, a mass for the Higgs of 170 GeV. This value lies near the middle of the possible mass range for the particle established by earlier experiments. This result not only restricts the possible masses where the Higgs might lie, but it also demonstrates that the Tevatron experiments are sensitive to potential Higgs signals.
"These results mean that the Tevatron experiments are very much in the game for finding the Higgs," said Pier Oddone, director of Fermilab.
Combining results from the two collider experiments effectively doubles the data available for analysis by experimenters and allows each experimental group to cross check and confirm the other's results. In the near future, the Fermilab experimenters expect to test more and more of the available mass range for the Higgs.
The Standard Model of Particles and Forces--the theoretical framework for particle physics--predicts the existence of a particle, the Higgs boson, that interacts with other particles of matter to give them mass. The mechanism by which particles acquire different mass values is unknown, and finding evidence for the existence of the Higgs boson would address this fundamental mystery of nature.
The CDF and DZero experiments each comprise some 600 physicists from universities and laboratories from across the nation and around the world. Currently, Fermilab's plans call for the Tevatron experiments to continue operating through 2010. In that time, both groups expect to double their analysis data sets, improving their chances to observe the Higgs.
Scientists expect operations to begin at the Large Hadron Collider at CERN, in Europe, sometime later this year. Observation of the Higgs is also a key goal for LHC experiments.
The Tevatron accelerator and the experiments are operating at peak performance. The Tevatron continues to break records for luminosity, the number of high-energy proton-antiproton collisions it produces. The more luminosity the Tevatron delivers, the more chances experimenters have to see the Higgs. Moreover, by continually improving their experimental techniques, the CDF and DZero physicists have been able to boost their sensitivity to the Higgs and other phenomena by more than the margin afforded by the increased data alone.
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