Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=207644
Story Retrieval Date: 4/1/2015 11:35:50 AM CST
Produced by Joanna Carver/MEDILL. Photos courtesy of CERN.
CERN is closing in on the Higgs boson, a particle that explains why matter has mass.
What is the Higgs? It matters to matter.
Technician Louis Rose-Dulcina installs equipment at CERN, the massive atom smasher in Switzerland, where scientists recently found a particle that may be the elusive Higgs boson.
CERN lies on the Franco-Swiss border and is home to more than 10,000 scientists and engineers from 113 countries.
Imagine a universe without stars, gas or any of us—just an endless expanse of light and nothing else. That’s the universe without the Higgs boson.
The Higgs is theorized to give mass to all matter—heavy science that has proved remarkably popular since Fermilab Director Emeritus Leon Lederman controversially termed it “The God Particle,” in the title of his 1993 book.
“The God Particle means that it’s the most important particle, because it gives life to all the other particles,” said Luciano Ristori, a physicist at the Fermi National Accelerator Laboratory, near Batavia. “It’s the Higgs particle that allows all the other elementary particles to have mass. If it didn’t exist, all the particles would have zero mass, and everything would be just light.”
But what does that mean, anyway?
Physicist Dmitri Denisov, also of Fermilab, admitted that it’s not easy for scientists to explain it to one another. “Even for myself,” he said, “it’s not like I can imagine it like it’s a ball or a wave. It’s a mathematical equation where I can look at it and get an answer.”
CERN scientist Antonio Boveia, however, put it in metaphorical terms, “What we’ve discovered is there’s a pool of water that extends throughout everything everywhere. We’ve discovered a particle that’s a ripple in the pool of water that tells us that the pool of water exists.”
That's the Higgs.
CERN is the Swiss home for the world’s largest atom smasher, the Large Hadron Collider, which accelerates intense beams of protons and slams them into each other. Scientists from the U.S. and 36 other counties sort through the subatomic debris to unravel the mysteries of the universe.
Boveia’s pool of water is the Higgs field, and the particle that creates the ripple is the Higgs boson. The Higgs gives particles mass, and that is why matter everywhere exists.
British physicist Peter Higgs proposed the existence of the particle in 1964, based on his studies of mass in particle physics. Since then, the hunt has been on and is heading into the final round.
A little over a month ago it seemed almost certain that the Higgs had been found, when CERN announced on July 4 that scientists there had observed a particle consistent with what they expected of a Higgs Boson.
Not exactly a “toss your hat in the air” announcement, but, said CERN physicist Kyle Cranmer, “Particle physicists are a very conservative bunch.”
Cranmer, officially Convener of the Statistics Forum for CERN’s ATLAS team, has been involved with the search for the Higgs boson for 13 years.
CERN’s Higgs hunt is divided into two teams of scientists at experiments called ATLAS and CMS (Compact Muon Solenoid) hunt for evidence of a Higgs boson CERN’s Large Hadron Colllider, or LHC.
Within the LHC, protons collide at higher and higher energies. The scientists look for a signal that they have created a Higgs boson that mimics those in nature in one of these collisions. The problem is that the signal remains very elusive and looks a lot like the signals of other collisions—a tiny bump on a smoothly falling line.
“We’re looking for a needle in a haystack, or a needle in a stack of needles,” said Boveia, a member of the ATLAS team.
Boveia said that the particle CERN announced on July 2 behaves a lot like a Higgs boson, but that scientists need more data to be sure.
Cranmer is fairly certain that they’ve found what they’ve been looking for.
“We have definitely found something. I don’t think anyone’s doubting that we’ve found a new particle,” he said. “The fact that it’s doing what it’s doing, it’s safe to call it a Higgs boson.”
Cranmer, an assistant professor of physics at New York University, was in New York for his birthday on June 25 when he saw the CERN data and felt totally confident that the Higgs boson had finally been discovered.
“For me, that had removed all doubt,” he said. “I did a happy dance up and down the hallway.”
Some of Cranmer’s grad students were with him when he found out. In a time of such excitement and historic proportions, Cranmer said that the LHC still has an enormous amount of potential, especially in one of science’s biggest mysteries—dark matter, an invisible, elusive substance that makes up a huge chunk of the universe and holds together the galaxies.
“If we can put those two things together it will be a huge leap forward in terms of what we understand and in the attitude of young physicists,” he said.
Fermilab’s Ristori said that, throughout history, the biggest advances in science came after an unexpected discovery like the Higgs boson.
“In the long run we hope that this will teach us about nature,” he said. “When you find something you can’t explain, you know you’ve got something important.”
Until the Tevatron was shut down last September, Fermilab was running its own collisions in the search for the Higgs. Fermilab has two teams studying data from 500 trillion Tevatron collisions conducted between 2000 and 2011. Two days before the big CERN announcement, Fermilab made theirs: that there was a strong indication, but no direct confirmation, that Higgs boson exists.
“A week before the CERN announcement we were confident, but not 100 percent confident,” said Denisov, the spokesman for the DZero experiment. “I think that we were extremely pleased.”
While the discovery of the Higgs boson still hasn’t been totally and absolutely confirmed, the work that comes next is more routine. Over the next several years scientists will study the particle’s properties.
“It’s like when Columbus discovered America,” Denisov said. “At first it was very exciting, but then it takes hundreds of years to colonize and explore the land.”
One of the most controversial aspects of the Higgs boson is the dreaded term Nobel Prize Winner Leon Lederman assigned to it in 1993, “The God Particle,” in the title of his book, “The God Particle: If the Universe is the Question, What is the Answer?” The name seems to imply some relation to religion or spirituality, raising consternation and even backlash in the scientific community even while bring immense popular attention to particle physics.
“It’s a marketing term,” Boveia said. “It doesn’t really have anything to with what the Higgs Boson is or what physicists think of it. It’s not some kind of mystical object.”
“It has nothing to do with religion,” said Ristori. “It’s misunderstood. The God Particle has nothing to do with God, of course. Science and religion are two completely independent fields, at least that’s my view.”
“It does strike some tension between religion and science, when there’s no need to," Cranmer said.
Cranmer said that he recently discovered from a pair of international friends that in Brazil, the Higgs boson is called “God’s Particle” and in Israel, it’s “The Godly Particle.”
Still, “The God Particle” raised popular awareness of just how important the Higgs boson is.
“As bad as the name is, it’s right,” Cranmer said. “It does play a very important role in the universe. Without it there’d be no life on Earth.”
Cranmer related being in a taxi in New York last week and seeing Jeopardy playing in the back seat. One of the questions was about the Higgs boson.
“It’s something that will be here forever,” he said. “It’s the kind of thing that a thousand years from now, people will be talking about this transition we’re going through."