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The Brian Cox & Robin Ince Sort of Chat Show – Episode 3

The Brian Cox and Robin Ince Sort of Chat Show continues…

When we last left them, Brian had decided consciousness was just an emergent property…

Robin – So, this year in physics one of the great things was Peter Higgs’ Nobel Prize and not even winning the Nobel Prize but not knowing about it until a neighbour shouted, well done, and he said, what for, and they said, you’ve won the Nobel Prize for physics, and he said, oh, I didn’t know about that, I was in the pub.  Now that’s one of the better ways of winning a Nobel Prize, I think, just being in the pub, I think he wanted some grilled trout and a pint of bitter.  So… 

Brian – Grilled trout? What kind of pub do you go to?

R – That’s what he wanted, that’s what he had!

B – Oh, that’s what he had?

R – Yeah, no, ‘cause the academy were apparently ringing up and going, well where is he? We’ve got to tell him he’s won the Nobel Prize for physics and …

B – He’s a modest man.

R – He went to the pub!

R – Yeah, he was really charming at the Cheltenham Science Festival.  So I presume in some ways that’s not this year in physics because what he’s winning that for is such a…kind of, the length of time of that work…

B – No but what’s… 

R – …so many people…

B – What’s interesting now, though, is to characterise that particle that’s been …

[phone goes off]

R – It’s a guest appearance by Jonathan Ross! Ah …

B – Ah…

R – what?

B – Yeah.

R – Sounds like Chris Hadfield’s arriving!

B  [playing with phone] Sorry about this, this is very good. Alright, yeah, OK. That’s enough. [puts phone away]

R – Right, so, ah …

B – Yes, the Higgs.

R – Peter Higgs.

B – So, what we have to do now is characterise that particle that’s been discovered. So it is…I would say certainly now it’s a Higgs boson of some kind, but there are many different Higgs particles; there are many different theories that give rise to different Higgs particles with different properties.  One of the theories is called supersymmetry which is still sort of hanging in there, which is the…it provides a natural candidate for dark matter.  So dark matter’s this stuff out there in the universe – five times as much as there is normal matter – which is certainly there, astronomers have measured it in many different ways, it’s there, it’s probably a particle but not the solid particles out of which we are made, so a new particle that’s yet to be discovered.  And those theories that present a very strong candidate for dark matter particles – one of those is called supersymmetry, – in those theories there are five Higgs in what’s called the Minimal Supersymmetric Standard Model, five Higgs particles.

And there can be scenarios where one of the Higgs particles looks very Standard Model-like.  So whether this thing is a Standard Model Higgs particle or not requires precision measurements, which is one of the reasons the LHC has been upgraded.  And the thing to remember at LHC is… 

R – So can you run through what upgraded, just so people know: what does that mean?

B – Well, it’s having a little bump up in energy again so it will collide particles with more energy, but more importantly it will collide more protons. Cause particle physics is quantum mechanics, it’s statistical. Basically, the theories say if you collide – and I can’t remember an exact number – if you collide so many billion protons together you’ll make one Higgs particle; if you collide twice that number together you’ll make two Higgs particles.

So there’s two things, there’s energy, that you need enough energy to make the things in the first place, but there’s also the number of protons you can collide together. And so the upgrades are a combination of those things which give you…the upshot is that you get more Higgs particles and if you’ve got more of them then you can watch them decay into other particles and you can precisely characterise their behaviour and see which kind of Higgs particle it is.

And then there’s a lot to do, even if it’s a so called Standard Model Higgs,  which is just one of them, it’s the one that was predicted all those years ago.  Then you’ve got to map out what’s called the Higgs potential, which is essentially the way which this Higgs field behaves, the precise features of it, and to do that you’ve got to make very precision measurements, in particular, you’ve got to see how Higgs particles talk to other Higgs particles and so you’ve got to make thousands, tens of thousands of them,  so you really want a Higgs factory to characterise it.

R – So, for you, is that the most exciting thing that now that, like so many things in science, you know, once there is an answer, rather than you know, it’s not an end, therefore…

B – No, it’s not.

R – …it becomes even more exciting.

B – It’s not.

R– By having a clear answer, cause at one point you said you would, there was a little bit of you that every now and again, there were certain ideas in science that you would like them to be proved wrong. I mean…

B – Oh, with the Higgs.

R – …with last year, with things like…I know a few physicists who…in some ways they were quite excited if that turned out to be wrong.

B – Well, the Higgs, yeah, I mean, I wrote a paper while ago on physics without a Higgs boson at the LHC, and they’re the worst scenarios you could imagine but they were narrowed down by the data. I mean, the remarkable thing…Peter Higgs himself would say that when he wrote that theory in the 60s with colleagues Kibble and others, they didn’t…I don’t think they really thought it was a real description of nature, they just thought that it was an interesting observation, you know, given this theory then look, you can do this, and you can generate masses in this particular way.  So it was very elegant and nice but it was over the decades as the thing wasn’t ruled out and circumstantial evidence came out from doing particle physics, it kind of cemented itself as something most people expected.  But it didn’t have to be, you’re right, it would’ve been very exciting if there hadn’t have been one.  Something had to happen at LHC. So LHC had sufficient energy such that those proton proton collisions were not able to be described by our theory without the Higgs at those energies.  So you have a theory that’s incomplete without the Higgs.

But now, now you focus down on this, it’s a fundamentally different type of particle.  So we have matter particles and force carrying particles, now we have a third type which is this Higgs thing, this scalar from a meson scalar particle, completely different, possibly the same thing that caused inflation in the early universe, the same type of thing, but possibly not, so,  you know.

So it’s a new vista in a way, a new piece of physics, a new type of physics that now we know is there, so now we can start doing real work on it.