Scientists close in on linchpin of physics, the ‘God particle’
By Brian Vastag and Joel Achenbach,
If rumors were dollars, the arcane world of particle physics would have enough cash to solve the Euro crisis.
For weeks, statements circulating on physics blogs have hinted at the discovery of an elusive particle essential to our understanding of how the universe works.
Called the Higgs boson, this particle — if spotted — would all but complete the fundamental theory of particle physics, known as the Standard Model. Confirmation of the Higgs would solve the mystery of why matter has the property that physicists call mass — the resistance to being shoved around.
If the Higgs does not exist, there’s a gaping hole in physicists’ explanation of nature’s deepest structure.
To search for this cosmic linchpin, the European Organization for Nuclear Research (CERN) built the biggest machine on Earth, a $10 billion circular tunnel some 17 miles long underneath the French-Swiss border called the Large Hadron Collider. Inside it, scientists smash together subatomic particles at astounding speeds. Sifting the debris offers clues as to whether the Higgs exists and what, exactly, it might look like.
On Tuesday, CERN scientists will unveil the latest results from two teams racing to spot the elusive quarry.
These new results are “sufficient to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the Higgs,” read a CERN statement announcing a news conference Tuesday.
Translation: We’re inching closer, but we’re not there yet.
“We are really getting to the end of hunting for this Higgs particle,” said Jacobo Konigsberg, a physicist at the University of Florida and a member of one of the two CERN teams.
Several CERN scientists said the two teams — comprising some 6,000 scientists — have enough data to strongly hint at a Higgs boson of a certain type. But the teams do not have enough data for a conclusive discovery.
As Konigsberg rushed on Monday to finish a scientific paper describing the latest results, he admitted some fatigue. “I’m a little weary of making such a big deal about this right now. Things are not going to be so black and white,” he said. “We’re entering a fuzzy area where you see some fluctuations but you can’t yet attribute them to the birth of a new particle.”
Theories developed in the 1960s and 1970s say the Higgs boson should give rise to a force field that permeates the universe and imbues other particles — such as protons and electrons — with their mass, which is not their weight, but rather their resistance to efforts to move them.
Don Lincoln, a physicist at the Energy Department’s Fermilab in Illinois and a member of one of the two CERN teams, likened the Higgs field to a pool of water. Just as a barracuda can knife swiftly through water, some subatomic particles — such as electrons — speed through the Higgs field, giving them very little mass. Other particles — akin to blubbery whales — create more drag, making them more massive.
“It’s an important particle, because it’s not just a particle, it’s also a force field that touches every other particle,” says physicist Joe Lykken of Fermilab. Lykken, a member of one of the teams searching for the Higgs, said of recent events, “The excitement is higher than anything I’ve seen in high-energy physics in the past 20 years.”
Because it has such cosmic significance, the Higgs is often referred to in the media as “the God particle,” the title of a book by physicist Leon Lederman. The particle’s more orthodox name is in honor of theorist Peter Higgs, who predicted its existence in 1964.
The Higgs is central to the Standard Model, which for physicists is the equivalent of the periodic table, as it describes all the known particles and forces in the universe.
“If the Higgs particle and Higgs field do not exist, then our whole conception of how elementary particle physics works is wrong,” said Gregory Tarle, a University of Michigan physicist and former member of one of the two CERN teams.
Or, as Lincoln puts it: “We’ve got this last dangling loose end in the theory and we want to find it.”
The Higgs is so elusive that, even with the $10 billion collider, there’s no way to see it directly. Theories suggest the Higgs is created in collisions of subatomic particles, but it only exists for about a yoctosecond, or one septillionth of a second. It then decays into other particles. The scientists at CERN study the debris field for signals consistent with a Higgs having decayed.
“It’s really a very hard problem,” said Lincoln, author of a book about the Large Hadron Collider called “The Quantum Frontier.” “That’s why we need so much data.”
Because scientists employ an indirect method of finding the Higgs, they have to be wary of mistaking some other phenomenon or a statistical quirk for a genuine discovery. And so physicists do not consider data conclusive until the odds of a fluke have been reduced to less than a million in one. The CERN data have not reached that certainty, several sources said.
CERN physicists say conclusive evidence of the Higgs should arrive next year, after the two collider experiments collect more data. The Large Hadron Collider is fallow for winter and will restart next spring.
To add to the intrigue, physicists at Fermilab say they still have some skin in the Higgs game, that the Europeans have not won the race yet.
Fermilab shuttered its long-running particle collider, the Tevatron, in September. But scientists are still sifting the data, looking for hints of the Higgs. That data will be made public in March, said Fermilab physicist Rob Roser.
Eventually, the CERN experiments will outrun the Tevatron, Roser said. But “no matter what they show tomorrow, people are going to want to see what the Tevatron has to say.”