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Cornering the Higgs

  • Posted 07.05.12
  • NOVA

On July 4, 2012, scientists at CERN used the word "discovery" to describe the results of experiments designed to prove the existence of the Higgs boson, a particle that gives mass to the universe. Host Marco Werman of PRI's The World gets a down-to-earth layman's analogy for what it means to say that a particle "gives mass," finds out why it's called the "God particle," and hears from a member of one of the teams that found the new particle, Jordan Nash of Imperial College London, on what this means for him personally and for physics.

Listen to the story.

A professor from one of the CERN teams explains what this experimental result means for the future of physics.

Marco Werman: I'm Marco Werman, this is The World. It was about as close as particle physicists come to shouting "Eureka!" In a packed conference room today in Geneva, scientists AT the European Organization for Nuclear Research, known as CERN, announced that they had discovered a new subatomic particle. They think what they've found is the long-sought Higgs boson. The physicist after whom it's named, Peter Higgs, was in the crowd.

Peter Higgs: Well, I would like to add my congratulations to everybody involved in this tremendous achievement. For me it's really an incredible thing that it's happened in my lifetime.

Marco Werman: Indeed, it took a long time to find the particle. Higgs and other scientists first theorized its existence half a century ago. Another physicist who came up with the idea for the particle, Tom Kibble, explained its significance.

Tom Kibble: Well, it's the last missing piece of the Standard Model of particle physics, which very successfully explains all the experimental evidence that we have, and this piece has to be there to make the model work.

Computer simulation of an event in which the decay of a Higgs boson produces four muons Enlarge Photo credit: CERN/Photo Researchers, Inc.

Marco Werman: Okay but wait a minute, I'm not sure I understood that. What does that mean? David Baron is The World's science editor and we're going to see if he can explain in lay terms just what the heck this Higgs boson is.

David Baron: I'll do my best, Marco.

Marco Werman: Okay so people are calling this the "God particle." I understand it has something to do with why matter has mass. Explain that.

David Baron: Right. Well, the "God particle" is kind of a misleading name for it. We might get to that in a minute, but yes, the big question is why do some particles have mass? And why are some heavier than others? And the theory that was devised fifty years ago was that empty space isn't actually empty, that it's permeated by this energy field, which is called a Higgs field, and some particles interact more with the Higgs field and as they move through space kind of get slowed down. And this field, if it exists, should have a particle with it and that's the Higgs boson.

Marco Werman: David, could you maybe state that in a simpler way using an analogy? I'm always good with analogies.

David Baron: Absolutely, right. Well one, that I've heard that I like a lot, is imagine if we all lived underwater, if we were living in this invisible medium, but we found that it was kind of hard to move through it. And some people or some things, like a moray eel can move through water very quickly, a blue whale has a little more trouble, it goes more slowly. But what is this thing called water? Well, if we're living in it, how would we prove that water exists?

"Leon Lederman, a famous Nobel Prize-winning physicist, came out with a book some years ago about the Higgs boson.  He wanted to call the book the "God-damned particle" because it was so hard to find."

Well if water exists, there should be these tiny particles that make up water. And those are of course water molecules. Well it's the same with this theorized Higgs field. If the field exists, there should be a particle associated with it. And this particle, which it took a very long time to create and find, that would be the Higgs boson. So it's sort of like a particle of water but it's in this energy field that permeates space.

Marco Werman: Okay, I think I get it much better now. So why do people call it the "God particle," David? Back to that God issue.

David Baron: Yeah, yeah. Well, that—it turns out it all comes from an unfortunate marketing gimmick. Leon Lederman, a famous Nobel Prize-winning physicist, came out with a book some years ago about the Higgs boson. He wanted to call the book the "God-damned particle" because it was so hard to find. It was his editor who thought a better title would be the "God particle" and it stuck. But this is not necessarily the most important particle out there. It's one of the many important particles that explain how the universe works. But the "God particle"—great marketing gimmick, not sure it really means much.

Marco Werman: David Baron, The World's science editor. Thank you as always, David.

David Baron: Thanks, Marco.

Marco Werman: For the scientists involved in today's announcement, they're not just celebrating, they're figuring out what work comes next. We caught up earlier today with Jordan Nash. he's a professor of physics at Imperial College London and a member of one of the teams that found the new particle. He spoke to us from CERN, the physics lab in Switzerland, and explained why it took so long to find a particle that was predicted by a theory half a century ago.

Jordan Nash: Well, it's a really beautiful mathematical idea, but it didn't have any predictions about the properties of this particle. It didn't tell us what it would weigh or where we should look for it. It just told us that it would be out there and interact with every other particle.

"What we did was predict that such a particle could exist on the basis of a beautiful mathematical theory..."

So it just has taken ages to search for it. It's been something that required us to build this fantastic machine, the Large Hadron Collider, to have enough energy in our collisions to produce it. Because it turned out this particle itself is extremely heavy.

Marco Werman: Right, I mean and I think that's kind of interesting, because basically this is not a discovery—you reproduced the Higgs boson.

Jordan Nash: It depends what you call a discovery. We have found a mechanism. We've found a particle that does this. We've produced it in the lab. What we did was predict that such a particle could exist on the basis of a beautiful mathematical theory, and we are finally seeing in the lab something that indicates this very clever, very elegant mathematical idea as being something that reflects what is actually there in nature.

After a Higgs particle is created, quantum fluctuations convert it into a particle-antiparticle pair, which recombines into two photons. Enlarge Photo credit: Courtesy Frank Wilczek

Marco Werman: You said before we started speaking that this is a fantastic day for science. but I've heard that some physicists are experiencing kind of a tinge of disappointment at finding what seems to be the Higgs boson particle, as if this discovery was a final piece of A puzzle to understand the universe. Do you and your colleagues now know all there is to know about the universe?

Jordan Nash: No, this is really just a start. It's a fantastic moment where we've actually discovered something new. And it's a piece of the puzzle that was really holding up our future progress. And it's going to be the start of a journey of really understanding it.

So it's going to give us a lot of excitement and discoveries to look forward to over the coming years. And we'll want to really produce a lot of them to understand how they work and really open up a new adventure in looking at the next phase of discovering how the universe is put together.

Marco Werman: And for physicists such as yourself, when does the celebrating the Higgs boson end and the quest for new discoveries begin?

Jordan Nash: Oh we've started the new quest already. We're busy trying to understand what all this means. We've shown you the first hints, but we're already thinking about how we're going to attack this problem. I have to say this is probably one of the most spectacular discoveries in my career, and it's really exciting to know that now we're on the start of a journey to really understand in depth what's going on. And we have the tools now to do it.

Marco Werman: Jordan Nash, a professor of physics at Imperial College London. He's also a member of one of the science teams at CERN in Switzerland that announced today the discovery of a new particle, likely the Higgs boson. Professor Nash, congratulations to you and the team at CERN. Thank you.

Jordan Nash: Thanks very much, Marco.

Host Marco Werman of PRI's The World interviews The World's Science Editor, David Baron, and Jordan Nash, Professor of Physics at Imperial College in London.

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