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Duration:10:34
Uploaded:2011-10-03
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In which Hank chats with the deputy spokesperson for the CMS detector at CERN.
Hank Green: So, can you tell me about who you are for a moment?

Joe Incandela: So, I'm a professor at the University of California Santa Barbara. I'm the deputy, um, head of the experiment of CMS and the elected next head of the experiment. We go- the title of the experiment head goes as spokesman, as you know, or spokesperson. But it's an executive position, it's not a communication position.

Hank: So how- how did you get here?

Joe: That's a good question. 

Hank: (laughs)

Joe: I have been in particle physics at colliders -- hadron colliders like the LHC -- for actually many, many years since about 1987. I was involved in the SPS, which was the, uh, big accelerator here where the W and Z were discovered. I moved to the Tevatron, at Fermilab. (0:49).
Um. After having looked for the top quark here I wanted to go to the Tevatron and find it there. And I joined CDF and I led the B-tagging group which actually had the strongest signal of any group at the Tevatron in '95. Part of the reason that we had such a strong signal was that we had a micro-vertex detector made with silicon strip sensors.
These are very thin wafers with fine strips on them and you can get a very, very, very precise position of where the particles pass through these wafers. (1:20) You can project those back to the origin and you can see that if they don't project back to the beam line, meaning that they came from some particle that traveled away, then decayed.
And that's how we're to see the Bs, OK, which were crucial to finding tops, because top quarks always decay to a B and a W.
That was a big, new addition to hadron collider physics that I had gotten excited about, so I worked on that at the Tevatron, then I led the silicon detector center at Fermilab for a while, and built some big silicon detectors for the CDF experiment, and finally, someone came to me from CMS and asked if I would help build the silicon for CMS.
I ended up leading the construction of about half of the -- uh -- the tracker.

Hank: Okay

Joe: And that went, that went very well; and, then the spokesman at the time, uh, liked my work. The deputy then became the- the deputy spokesperson at that time became spokesman and asked me to become deputy physics coordinator -- and that was in 2007. And, then the next spokesman -- the current one -- Guido Tonelli -- asked me to be deputy to him as spokesman, so sort of a number of things, you kind of build up your reputation a over a long time with these experiments, and then you rise to one of these positions, then they burn you out and you go back down to the heap.

Hank: (laughs)

Joe: (laughs)

Hank: Can you give me a very brief explanation of the standard model?

Joe: It's basically a model that describes all of the fund -- almost all of the fundamental, uh, particles in the directions that we know about. One piece that's missing is gravity, which is very hard to incorporate in a quantum theory; and, the standard model's all quantum field theory.
There are three main forces that we think of. One is electromagnetism, the other is the weak nuclear force, and then there's the strong nuclear force; and, those three are described in the standard model. In fact, two of them are unified. The weak nuclear force and electromagnetism turn out to be a sort of the same, different aspects of the same thing with a [*inaudible*] connection. (3:10)

Hank: So it's always kind of seemed to me, I mean from a very layperson's standpoint that quantum mechanics is, uh, so weird, you know it's, it's explaining something, it's not the explanation.

Joe: Quantum mechanics is, is really, believed to be complete. We're tempted to say, you know, like Einstein, that God does not roll dice; because, uh, quantum mechanics is this probabilistic model, of, uh, a way to, uh, you know, you describe processes in terms of probabilities not in terms of anything definite and that really bothers us that we cannot predict things definitely, and there, there are things like Bell's theorem that explain that yes this is it, this is how it goes, you can't go beyond this.
I have to say that I often question it myself and wonder if, um, you know if, if somehow, you know where we're really living is a projection in a smaller space and we're not seeing everything. You know that quantum mechanics might be an effective theory inside of a bigger theory. But, I'll tell you this: most theorists will not -- really don't want to entertain those discussions.

Hank: (laughs)

Joe: (laughs)
What we're doing here is going beyond quantum mechanics, beyond -- sometimes beyond quantum field theory and trying to understand, uh, you know really the basic structure of the universe, whether there are additional dimensions.

Hank: You're working in Europe and you just alluded a little bit that, you know, different particles are called different things in different languages, uh, is language a barrier for you?

Joe: Not generally, because I've worked at CERN off and on a lot of my career, um, I actually study a lot of the languages, so I know, I'm fluent in French, I'm fluent in Italian as well, I can get -- understand Spanish pretty well. With Romantic languages I have a good shape. Everyone speaks English.

Hank: Ah (laughs) that helps.

Joe: Well that helps us a lot. It also makes it very hard to learn a foreign language.

Hank: I've been hearing that the Higgs is, is, dis-, un-, like disprovable, like you can say it doesn't exist. There's an experiment that we can do that will know. Um, that seems unlikely to me. It seems very difficult to prove that something doesn't exist.

Joe: So it depends really how you phrase it and we can phrase this, the question that way.  So, the strictest form of the standard model Higgs has very, very specific predictions.

Hank: Right.

Joe: Really down to -- and we can predict down to incredible precision. We don't know the mass of the Higgs; but, for any given value of the mass we know exactly what would happen for the standard model Higgs. So, that guy we can put out of his existence.
If you go into much more, um, exotic models, possibly true models of what really goes on in nature, it's possible that we would miss it. But when people say we can rule out the Higgs, they're talking about a specific item, the standard model Higgs. And, that in itself is a major, major thing. We've known for a long time that the standard model is not the end of the story.

Hank: Right.

Joe: But this would kind of really put a nail in its coffin.

Hank: What else is missing from this standard model? You said gravity.

Joe: There are five things we know of that are missing besides gravity. The fifth one I always forget.

Hank: (laughs)

Joe: We can sit here like, like me occasionally thinking: my God we've spent so many years of our lives, I've spent fifteen years preparing this experiment, what if we don't find anything, you know? It doesn't work that way because we know there has to be something that's got to give, and the reason is we know that there's dark matter. We don't know what it is but it's huge -- almost 30% of the universe, it's about five times more abundant than normal matter that we know and love.

Hank: It's 30% of the universe, but only five times more than normal matter. What is everything else?

Joe: Exactly. Almost everything else is dark energy, that's 70%. We are definitely in the minority. Normal matter is only 4%.

Hank: Well you say that, but I look around and I'm only seeing normal matter.

Joe: That's right, that's right.

Hank: I feel like I'm in the majority here in my office. 

Joe: And that's because we don't interact with the rest of it. And that's the problem. I mean, it's right... 

Hank: So here, it's not - it's not like hanging out somewhere else. It's everywhere.

Joe: It's very like -- everywhere. Dark matter in particular. We don't know -- I can't even talk about, um, dark energy because I don't know that we have any good idea of what it is. 

Hank: Right. 

Joe: The dark matter we have actually many candidates of what it could be. And they gives these certain particles that don't interact with normal matter very much; so, it's super weakly interacting. So you could have a ton of it passing through your head right now and you wouldn't feel it. 

Hank: Doesn't it have to have mass in order for it to have - 

Joe: It has mass. Sure, sure. 

Hank: It just doesn't interact. 

Joe: What's holding you from falling to the center of the earth right now?

Hank: Ma chair.

Joe: It's really mostly electromagnetism. Of course what's holding the chair together

Hank: Oh, yeah, the - the electrons squishing together. 

Joe: It's almost all electromagnetism. And that's super strong compared to gravity. It's, you know, unbelievably strong, right. So we know there's dark matter, we know there's dark energy. Those two combined are over 95% of everything that the universe is made of. Then there's the fact that neutrinos have mass. The standard model does not predict that. There's the fact that the universe has had to have have a period of inflation. And then there's this causal connection from one extreme to the other, where if you look in one direction of the universe, and you look in the opposite direction these regions should not be -- in any way have been able to talk to each other. They should be causally disconnected. And yet, they seem to have a lot of correlations.

But there are these 5 things that we don't know.  And then there's the connection to gravity. So there has to be something else out there. I've - my group is looking for dark matter, a dark matter candidate. I think that's a very exciting way to go. The Higgs will be very interesting. I would say, if we find it. Or don't! Either way, it's a major result.

Hank: Would a larger collider allow you to find more?

Joe: Higher energy would have helped a lot. To get to the energies that we need to, we have to go to very intense beam. And that means that when we -- when the beams cross, many pairs of protons interact, which is a bit of mess. And if we'd gone to higher energy, we wouldn't have needed to go to such high intensity. That was part of the intention of, the desire of the SSC. The SSC would have been a great machine, and we know, um, it could have helped. But I think what we have here, at the LHC is adequate for a huge amount of the, the phase space. And, the LHC can also be upgraded some day with stronger magnets to get to energies close to what the SSC would find.

Hank: Yeah.

Joe: So, we may get there anyway. But, right now were sitting in a region which is very, very exciting -- even at half the design energy. We're already able, as you see -- if you know results that have come out -- that we're very close to nailing down the standard model Higgs. So, next year we'll, we'll be able to say something definitively.  We will find it, or we don't. If we find it, then we have to study it; and, the details may tell us a lot about where to look next. And, if we don't find it -- although, it will be hard to explain this to our funding agencies -- it's a much more exciting situation.

Hank: (laughs) Where you get to make up your own particles that have your name on them.

Joe: Uh, maybe. It could be some interesting, uh... Who knows?

Hank: I very much appreciate you taking the time to talk to me this evening.

Joe: It will be great for people to keep tuned; and, um, and see what we come up with. And, hopefully it'll be something... surprising and highly exciting

Hank: Well, great. Thanks, Joe.

Joe: Take care.