Scientists Blast Antimatter Atoms With A Laser For The First Time

Dec 19, 2016
Originally published on May 2, 2017 1:32 pm

In a technological tour de force, scientists have developed a new way to probe antimatter.

For the first time, researchers were able to zap antimatter atoms with a laser, then precisely measure the light let off by these strange anti-atoms. By comparing the light from anti-atoms with the light from regular atoms, they hope to answer one of the big mysteries of our universe: Why, in the early universe, did antimatter lose out to regular old matter?

"This represents a historic point in the decades-long efforts to create antimatter and compare its properties to those of matter," says Alan Kostelecky, a theoretical physicist at Indiana University.

Antimatter sounds like something out of science fiction. "The first time I heard about antimatter was on Star Trek, when I was a kid," says Jeffrey Hangst, a physicist at Aarhus University in Denmark. "I was intrigued by what it was and then kind of shocked to learn that it was a real thing in physics."

He founded a research group called ALPHA at CERN, Europe's premier particle physics laboratory near Geneva, that is devoted to studying antimatter. That's a tricky thing to do because antimatter isn't like the regular matter you see around you every day. At the subatomic level, antimatter is pretty much the complete opposite — instead of having a negative charge, for example, its electrons have a positive charge. And whenever antimatter comes into contact with regular matter, they both disappear in a flash of light.

"What you hear about in science fiction — that antimatter gets annihilated by normal matter — is 100 percent true," Hangst says, "and is the greatest challenge in my everyday life."

Because if his team makes antimatter and then it touches the walls of its container ... then poof! It's gone.

He and his colleagues have spent years figuring out how to make the antimatter version of simple hydrogen atoms. They then trap and hold these anti-atoms in a vacuum using strong magnetic fields.

"We can keep them for a long time," Hangst says. "We've demonstrated we can keep them for 15 minutes without losing them."

In the journal Nature, his team reports that they've now used the special laser to probe this antimatter. So far, what they see is that their anti-hydrogen atoms respond to the laser in the same way that regular hydrogen does.

That's what the various theories out there would predict — still, Hangst says, it's important to check. "We're kind of really overjoyed to finally be able to say we have done this," he says. "For us, it's a really big deal."

Understanding the basic properties of antimatter is an important step toward understanding why we even exist. When the universe began, scientists think, there should have been equal amounts of antimatter and matter — which means they should have destroyed each other completely.

"But something happened, some small asymmetry that led some of the matter to survive," Hangst says. "And we simply have no good idea that explains that right now."

That's why he and his colleagues want to understand whether matter and antimatter truly obey the same laws of physics. And theoretical physicists watch these experiments with awe.

"Just the concept that you can make an anti-atom, an atom made of antimatter, is a real gee-whiz thing," says Chris Quigg, at Fermilab, near Chicago. "Anybody has to be impressed by that."

There are a lot more subtle measurements of antimatter left to do. And once experimentalists develop this kind of new tool, Quigg says, who knows what else they'll be able to do with it in the future.

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ARI SHAPIRO, HOST:

Scientists announced a technological tour de force today. They used a laser to probe antimatter. That is a step towards understanding a big mystery - why there is so little antimatter in the universe. NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE, BYLINE: Antimatter has fascinated Jeffrey Hangst for almost his whole life.

JEFFREY HANGST: The first time I heard about antimatter was on "Star Trek" when I was a kid.

(SOUNDBITE OF TV SHOW, "STAR TREK")

LEONARD NIMOY: (As Mr. Spock) Bridge to engineering.

JAMES DOOHAN: (As Scotty) Aye, Mr. Spock, the emergency bypass control of the matter-antimatter integrator is fused.

HANGST: I was intrigued by what it was and then kind of shocked to learn that it was a real thing in physics.

GREENFIELDBOYCE: He became a physicist. He now works at Aarhus University in Denmark, and he founded a research group at CERN in Geneva, Switzerland, devoted to studying antimatter. Now, that is tricky to do.

Antimatter isn't like the regular matter you see around you every day. At the subatomic level, it's, like, the complete opposite. Your electrons have a negative charge. Its electrons have a positive charge. And whenever antimatter comes into contact with regular old matter, they both disappear in a flash of light.

HANGST: What you hear about in science fiction - that antimatter gets annihilated by normal matter - is a hundred percent true and is the greatest challenge in my everyday life.

GREENFIELDBOYCE: Because if his team makes antimatter and then it touches the walls of its container, poof, it is gone. He and his colleagues have spent years figuring out how to make the antimatter version of simple hydrogen atoms. They then trap and hold these antiatoms in a vacuum using strong magnetic fields.

HANGST: And we can keep them for a long time. We've demonstrated we can keep them for sort of 15 minutes without losing them.

GREENFIELDBOYCE: Today in the journal Nature, his team reports that they used a special laser to probe this antimatter. So far, what they see is that it responds to the laser in the same way that regular matter does. That's what the various theories out there would predict. Still, Hangst says it's important to check.

HANGST: We're kind of really overjoyed to finally be able to say that we've done this. For us, it's a really big deal.

GREENFIELDBOYCE: Because understanding antimatter is an important step towards understanding why we even exist. When the universe first began, scientists think there should have been equal amounts of antimatter and matter. They should have destroyed each other completely.

HANGST: But something happened - something - some small asymmetry that led some of the matter to survive. And we simply have no good idea that explains that right now.

GREENFIELDBOYCE: Theoretical physicists watch these experiments with awe. Chris Quigg works at Fermilab near Chicago.

CHRIS QUIGG: Just the concept that you can make an antiatom, an atom made out of antimatter, is a real gee-whiz thing. And anybody has to be impressed by that.

GREENFIELDBOYCE: There's a lot more subtle measurements of antimatter that need to be done. And Quigg says once experimentalists develop this kind of new tool, who knows what else they'll be able to do with it in the future? Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.