While researchers haven’t found the Higgs conclusively, one of them said there was an “excess of events” detected in particle-collider experiments that hints at where the Higgs could be found.
The announcement of new data obtained by experiments conducted by two teams at the Large Hadron Collider, the huge apparatus near Geneva, was closely followed by the global physics community.
No one expected a definitive discovery, and none was announced. But scientists who gathered in an auditorium for a seminar this morning at the European Organization for Nuclear Research (CERN) erupted in sustained applause at what seems to be a major step toward a scientific breakthrough.
The scientists don’t know the mass of the Higgs. But the latest experiments have excluded a lot of possibilities.
Fabiola Gianatti, a physicist representing the experiment named ATLAS, said that if the Higgs exists, its mass most likely is somewhere in the range of 115.5 to 131 billion electron volts (GeV), which is roughly 115.5 to 131 times the mass of a proton. That would support the Standard Model of particle physics and be in a range where further scrutiny might turn up more definitive proof.
“It would be a very nice region for the Higgs to be,” one of Gianatti’s slides said. But another slide cautioned: “It’s too early to draw definite conclusions.”
At the end of the seminar, CERN director-general Rolf-Dieter Heuer cautioned the assembled scientists against concluding too much.
“The window for the Higgs mass gets smaller and smaller. But it is still alive,” Heuer said. “Be careful, it’s intriguing hints in several channels in two experiments. But please be prudent. We have not found it yet.”
The Higgs boson is thought to be tied to a field (the Higgs field) that is responsible for giving all other particles their mass. Ironically, physicists don't have a specific prediction for the mass ofthe Higgs boson itself, so they must search a wide range of possible masses for signs of the particle.
Based on data collected at LHC's CMS and ATLAS experiments, researchers said they are now able to narrow down the Higgs' mass to a small range, and exclude a wide swath of possibilities.
"With the data from this year we've ruled out a lot of masses, and now we're just left with this tiny window, in this region that is probably the most interesting," said Jonas Strandberg, a researcher at CERN working on the ATLAS experiment.
The researchers have now cornered the Higgs mass in the range between 114.4 and 131 gigaelectronvolts (GeV).For comparison, a proton weighs 1 GeV. Outside that range, the scientists are more than 95 percent confident that the Higgs cannot exist.
Within that range, the ATLAS findings show some indications of a possible signal from the Higgs boson at 126 GeV, though the data are not strong enough for scientists to claim a finding with the level of confidence they require for a true discovery.
"Based on the predicted size of the signal, the experiments may have their first glimpse of a positive signal," University of Chicago physicist Jim Pilcher wrote in an email to LiveScience. "It is especially important to compare the results of two independent experiments to help reduce statistical fluctuations and experimental biases."
But it shouldn't be much longer before scientists can be sure if the Higgs exists, and if so, how much mass it has.
"We know we must be getting close," Strandberg told LiveScience. "All we need is a little bit more data. I think the data we take in 2012 should be able to really give a definitive answer if the Higgs boson exists."
The Large Hadron Collider is a 17-mile (27-kilometer) loop buried underneath France and Switzerland, run by CERN, based in Geneva.
Inside this loop, protons traveling near the speed of light collide head-on, and release huge amounts of energy in powerful explosions.
This energy then coalesces into new particles, some of which are exotic, hard-to-find species like the Higgs. The Higgs quickly decays into other particle products, which are then sensed by the detectors inside ATLAS and CMS. [6 Exotic Particles Explained]
The new results are based on data accumulated over 500 trillion proton-proton collisions inside the LHC.
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