Professor Roger Barlow on Higgs, the Boson and the Nobel Prize
Tue, 08 Oct 2013 16:53:00 BST
After disappointment of last year, when the bookies' favourite didn’t win, this year the Higgs’ Boson swept home to victory with the 2013 Nobel Prize for physics. For their original prediction of the existence of the particle, Peter Higgs of the University of Edinburgh and Francois Englert or the Univerite Libre de Bruxelle in Belguim were jointly awarded the prize. Dr Paul Elliott talked to particle physicist Professor Roger Barlow to find out more about the Higgs’ boson and the significance of its discovery.
“I am currently the Director for the Institute of Accelerator Applications here in Huddersfield but I was, and still am, a particle physicist.” Prof Barlow begins, “I’m not one of the people that worked on the experiments that discovered the Higgs but I have worked on many experiments that failed to discover the Higgs over the past ... in Germany, in Geneva, in America.” On the news that the Nobel Prize has been awarded to Higgs and Englert, Prof Barlow says, “I am please and today is just the icing on the cake! The big breakthrough came last year when the particle was actually found and we knew the idea had been right all along.”
But what is the Higg’s boson, and what does it do? “In the 1960’s, before I was around,” Prof Barlow jokes, “we had this beautiful theory that just didn’t work.”
Like all physical objects in the universe, we are all made up of particles, particles that form the atoms and molecules in our bodies. All the these particles, the electrons, the larger protons and neutrons and the quarks that form them and so on, were all described by a theoretical framework called The Standard Model.
Now, at one time or another we have all probably gingerly stepped onto the scales only to cringe as we look at the dial spin round. And therein lies the problem... whilst the standard model beautifully explained the behaviour of all these various particles, there was one aspect that couldn’t be explained: their mass. No particle should have any mass, they shouldn’t weight anything. What these theoretical physicists realised was that there must be an extra force field in nature that breaks certain symmetry properties within the standard model and therefore allows particles to have mass but allows the explanatory power of the standard model to remain intact.
“The photon, the particle of light, does have zero mass and this was a theory that said these other particles, these W’s and Z’s are like photons, but the W’s and Z’s do have non-zero mass as do the other particles. Higgs and Brout (now deceased) and Englert showed how to make it work by adding this extra field ... And this mechanism showed how to break the symmetry and would then allow the particles the have mass without violating the rule book.”
There is controversy surrounding the prize with a number of physicists having a solid claim to having made a significant contribution to the formulation of the Higgs field hypothesis. “Now that the dust has settled ... its fair to say that this was the cumulative work of a lot of people, Kibble, Hagan and others as well as Higgs and Brout and Englert but those were the three that specifically laid out how the mechanism was broken and Higgs was the one who wrote down, “and this means that there will be a particle associated with this field!” So I think it’s right that he gets his name on the particle but the three of them, of whom only two are now alive, get their name on the mechanism.
Reflecting on the significance of the work of the winners, Prof Barlow says excitedly, “It’s a beautiful example of how pure thought, somebody just scribbling down bits of equations and formulae can lead to massive accelerators, massive detectors, thousands of people working, lots of concrete and steel under the ground and finally, as a result, we know it’s there.”
So, job done? Is our picture of universe complete? “As usual, you answer one question, you raise a whole lot more. We still don’t understand why this field has the form that it has, we don’t understand why the mass [of the Higgs’ boson] is so different from all the other masses, so there are a lot of unanswered questions but we have come to the end of a chapter.”
The interview between Professor Barlow and Dr Paul Elliott was recorded in the Peter Higgs Suite of the University's Researcher Hub.
Paul Elliott: Professor Roger Barlow, perhaps you could just put things into context and explain your current role and your background in particle physics?
Roger Barlow: As you know, I am currently the Director of the Institute for Accelerator Applications here in Huddersfield, but I was and still am a particle physicist. I'm not one of the people that worked on the experiments that discovered the Higgs, but I have worked on many experiments that failed to discover the Higgs over the past God knows how long in Germany, in Geneva, in America, we didn't make a discovery but at least we got some publications out of it.
Today is just the icing on the cake, the big breakthrough came last year when the particle was actually found and we knew the idea had been right all along.
You want me to explain what higgs boson in 2 minutes, I will do my best. In the 1960s, which was before I was around, we had this beautiful theory which just didn’t work. And Higgs and Brout and Englert showed how to make it work by adding this extra field.
PE: So what was missing from this model? What was the thing that didnt work?
RB: The particles behaved as they should but they all had zero mass and had to have zero mass and this mechanism showed how to break the symmetry which would then allow particles to have mass, without violating the rule book.
PE: So we know that particles have mass, but the maths at the time didn’t provide any mechanism for it.
RB: Absolutely. You see the Photon, the light particle, has got zero mass and this was a theory which said well these other particles these W’s and say they're like Photons. But the W’s and Z’s had none zero mass as do other particles and Higgs showed how to break that.
And Higgs, I think it’s now the dust has settled and jury’s out, this was a discovery that came out a lot of cumulative work of a lot of people. Kibble, Anderson, and others as well as Higgs, Brout, Englert but those were the three that specifically laid out how the mechanism was broken.
And Higgs was the one who actually wrote down and this means that there will be a particle associated with this field. So I think it’s right that he gets his name on the particle. But the 3 of which only two are alive now which is why it’s only 2 prizes awarded, get their name on the mechanism.
And it’s a beautiful example of how pure thought, just somebody scribbling down bits of equations in a formula can lead to massive accelerators, massive detectors, thousands of people working, lots of concrete and steel, electricity on the ground, and as a result we finally know that its there
The Nobel Prize - this is a chocolate one, he'll be getting the real one - the Nobel Prize is just the icing on the cake. He's got the... they've got the esteem of his colleagues and of other scientists already.
PE: So job done? Nothing left to do in Physics?
RB: Ahh... No. It's as usual, you answer one question, you raise a whole lot more. We don't understand why this field has the form that is has, we don't understand why the mass is so different from other masses. There are a lot more unanswered questions. But we have come to the end of a chapter.
PE: Professor Roger Barlow, thank you very much.
RB: Thank you.