Scientists from the CDF and DZero collaborations have found their strongest indication to date for the long-sought Higgs particle after more than 10 years of gathering and analyzing data produced by the U.S. Department of Energy’s Tevatron collider.
Squeezing the last bit of information out of 500 trillion collisions produced by the Tevatron for each experiment since March 2001, the final analysis of the data does not settle the question of whether the Higgs particle exists, but gets closer to an answer.
The Tevatron scientists unveiled their latest results on July 2, two days before the highly anticipated announcement of the latest Higgs-search results from the Large Hadron Collider in Europe.
“The Tevatron experiments accomplished the goals that we had set with this data sample,” said Fermilab’s Rob Roser, cospokesperson for the CDF experiment at DOE’s Fermi National Accelerator Laboratory.
“Our data strongly point toward the existence of the Higgs boson, but it will take results from the experiments at the Large Hadron Collider in Europe to establish a discovery,” Roser stated.
Scientists of the CDF and DZero collider experiments at the Tevatron received a round of rousing applause from hundreds of colleagues when they presented their results at a scientific seminar at Fermilab.
The Large Hadron Collider results will be announced at a scientific seminar at 2 a.m. CDT on July 4 at the CERN particle physics laboratory in Geneva, Switzerland.
“It is a real cliffhanger,” said DZero co-spokesperson Gregorio Bernardi, physicist at the Laboratory of Nuclear and High Energy Physics, or LPNHE, at the University of Paris VI and VII.
“We know exactly what signal we are looking for in our data, and we see strong indications of the production and decay of Higgs bosons in a crucial decay mode with a pair of bottom quarks, which is difficult to observe at the LHC. We are very excited about it,” Bernardi noted.
The Tevatron results indicate that the Higgs particle, if it exists, has a mass between 115 and 135 GeV/c2, or about 130 times the mass of the proton.
The final Tevatron results corroborate the Higgs search results that scientists from the Tevatron and the LHC presented at physics conferences in March 2012.
Tevatron scientists found that the observed Higgs signal in the combined CDF and DZero data in the bottom-quark decay mode has a statistical significance of 2.9 sigma. This means there is only a 1-in-550 chance that the signal is due to a statistical fluctuation.
“We achieved a critical step in the search for the Higgs boson. While 5-sigma significance is required for a discovery, it seems unlikely that the Tevatron collisions mimicked a Higgs signal. Nobody expected the Tevatron to get this far when it was built in the 1980s,” said Dmitri Denisov, DZero cospokesperson and physicist at Fermilab.
The CDF and DZero collaborations submitted their joint Higgs search results to the electronic preprint archive arXiv.org.