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Legation. It's actually a regular part goods and field seminar, which we have every Thursday at this time.

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But we thought we would make something of this one to celebrate the legacy of our founder, Dick Dulles, who founded this group, I think, 52 years ago.

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And I say that we should have done something on the 50th anniversary, but to be honest, we are all so busy we forgot about it.

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Right. So. So today might be a good time to set that right.

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And I'm really delighted that so many of you, especially the alumni, have been able to come, and many others like Don there,

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who knew Dick personally and would be able to contribute their memories of Dick later will have a little event downstairs after this.

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But first, I want to say a few words about what has happened since Dick passed away.

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That was ten years ago. Well, the group that he started back in 63 has now grown to be about a dozen people.

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And this is us. We now cover all areas of particle physics.

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I thought this would be of interest to the family because initially, of course, Dick worked in phenomenology and many of us still do.

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That's all that lot down there. And we now, however,

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range across the entire spectrum of work that is being done in fundamental physics and its link with the nature of matter and forces, if you like.

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And in addition to 11 members of staff, one of whom is currently at CERN,

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there are about a dozen postdocs and about twice as many students approximate

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sign there because you're never quite sure how many of them are actually around.

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But you know, most of them are here. And if you want to know more about us and what we do, you're very welcome to look up our webpage.

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But what we have lined up for you today is a treat.

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We have two students of Dick Franklin's and Chris Llewellyn Smith who have very kindly agreed to come

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to talk about the scientific legacy because this is a seminar and we shall stick to that format.

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But they have agreed to make it accessible to a broad audience.

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And I therefore would like to ask first, Frank, to come up, and I'm told that if I lift this lid, it will automatically switch to it.

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And if it doesn't, then [INAUDIBLE] do something to me. So let us hope that works.

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There you are. Very good. And I'm told not to speak to you and to now give him the microphone.

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And while he's putting that on, actually other speakers today,

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nothing but perhaps some of the younger people here do not know everything about them as they should.

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So let me say that Frank, as I said, was a student of David's.

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I believe he was at Berlin and he got his after look, this build up.

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It was 1970 that he got his dphil. Yes, at least according to your Wikipedia.

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It must be true. Then it must be true.

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Following which he went to Stack and Daresbury and then soon before had him getting a permanent

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position that other for the high energy laboratory as it was then called back in 75.

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In fact, that's where I first met him some years later.

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And he was head of the theoretical physics group there from 1991.

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And subsequently he moved to Oxford in 2001 and retired about ten years later,

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although you really still have a link to Exeter College where he was a fellow,

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and I should mention that Frank is of course very well known for all his books.

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He also was awarded the Medal of the City of Physics for his outreach work and and an OBE in 2000.

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And I let him tell us about his experience of working here many, many, many years ago with big thanks very much.

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So. Well, Dick could have been a draughtsman or engineer, but he became a theoretical physicist.

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But these diagrams, his own work, the very first Dallas plot, he drew himself.

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And it was in the old days. Dick, Chris will talk about this more.

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So I won't say much more about this particular thing, but this was way, way back at a time when a particle called the CME Zone was behaving strangely.

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And eventually they had other people to discover the idea that mirror symmetry wasn't conserved.

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But these were Dick's drawings at that time. 40 years later, these Dalits plots, as they become known, have moved on.

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They're generated by computer, whether they're more beautiful now than they were when Dick drew them all those years ago, I'll leave it to you.

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The information that they have generated is vast.

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And indeed, thanks to Dalits plots which have been used to identify particles that live for a shorter amount of time,

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that it takes light to cross an atomic nucleus. We have books like this produced every two years, which we expect students to learn.

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So the the new Dalits plots began in 1960.

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I put new in quotes. What had happened there was that Dick had found this nice pictorial way of representing

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what happens after a shortlived particle decays into many other particles.

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And by making a diagram of these events, it was possible to identify special features.

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And this led to the discovery of new, very short lived particles called resonances.

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And the first example of one of these found in 1960 was given a name called the Sigma Sigma Star.

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And then shortly afterwards, another one called the PSI Star.

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And this led Murray Gell-Mann in particular to have the idea that all of these

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particles which were rapidly multiplying now were not independent of one another.

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They lived in sort of families, in families of eight and ten.

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And he decided to call it the eightfold way to give it a a sexy name.

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Now, that much is pretty well known.

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What I hadn't known until very recently was that Gilman talked about this at a school in Bangalore in 1961, and that Dick was in the audience.

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And the story you can check for yourself, because Roger Sacrum, who was there, wrote it up in this edition in physics.

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And Dick started pestering Gail man, because the idea of these families of eight and ten were all predicated upon the

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idea that behind the scenes there should be a three that gave rise to them.

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And so Dick started questioning Gail, man, about these triplets and saying, No, why are you ignoring them?

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And Gelman managed apparently to evade answering the question, despite Dick's repeated asking it.

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And Roger, sacred summary is that, you know, if Gelman had answered the question directly back then,

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then quarks could have been born in Bangalore in 1961 instead of waiting until 1964,

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when by that stage Gelman invented them and gave them the name, though I'm never sure whether he really believed in them.

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And George Zweig independently came up with the idea, and he certainly did believe in them.

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What I don't understand is why Dick himself in 1961, having pestered Gail Man about the fundamental importance of these triplets,

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didn't actually pick up there and then and start thinking about them.

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But that is, again, another thing in history.

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And although Gell-Mann and Zweig, again, are the people who are well known for inventing the idea of the quarks, Chris found a paper, I think,

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a year or so ago that Andre Pitman had produced in French earlier that year, which in essence has everything that you would call quarks buried in it.

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And for some reason he didn't develop it. But that's the strange history.

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So Dick didn't invent quarks.

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But having pestered Gail Mann, he was very quick on the uptake, and the following year he gave some lectures the school in laser push,

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and in these he taught all the lectures quark models for the the fundamental particles.

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And it's in there that he really set out his stall and I think turned this idea into a really concrete concept.

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And this is the first page of his his lecture. And it's interesting just to note down here the reactions to this,

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that these models of building things out of quarks are instructive and suggestive and have at present

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rather more contact with the experimental data than do more formal considerations based on group theory.

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I think that's a nod to Gail Mann. They are explicit representations of the group theoretical approach, of course,

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and so they are able to reproduce the group theoretical results, but in a more pedestrian and comprehensible manner, however.

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So for students, that's a great reason. I like pedestrian things.

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They involve dynamical assumptions going beyond the group theoretical structure and lead to further predictions which B can be tested experimentally.

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And that was a key thing.

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Having taken the ideas seriously to imagine that the proton and all these emerging resonances were genuinely made of three fundamental constituents.

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Dick then built upon that, and I think that his essential contribution is the following thing that the idea

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of quarks has been articulated by Gail Mann and Zweig and perhaps also Padman.

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Dick then said, If this is real, these things can be excited.

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Analogies to the way that electrons can be excited within atoms or that nucleons can be excited within nuclei.

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So can quarks be excited within hadrons?

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So you start off with three quarks in the lowest level, which we'll call the proton, and you can excite them into one neutral orbital angle momentum.

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And when you do that, you have to be careful about keeping track of the correlations between spin and flavour,

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as we now call it, that the Palli principle requires. And you get a family with a certain structure, which she sort of showed there on the left.

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If you excited twice the two levels, you get a different sort of structure.

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It would be show on the right. And he did that in 1965.

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And in the 2014 edition of the Particle Data Tables,

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you see that the remarks that he made back there 50 years ago are completely in accord with what we know,

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certainly at this first level and again at this second level.

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And I find that remarkable when you look back at the thing while doing this, I noticed something odd, actually,

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that for physicists here that he has got the most triplets on the left there

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with the spin one half at the top and then the seven halves at the bottom,

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the familiar inverted form that you find in nuclear physics and opposite to what you find in atomic physics.

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So that whether it was an accident, seems to be a deliberate belief that there was a parallel between what he was doing

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here with the quarks in Nucleons and the way that nuclei themselves are built.

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So that is where it was when I came here and was given the task of believing these crazy particles that nobody had ever seen.

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And the question was for me, were these ideas, were these particles real or were they just figments of the imagination of people here at Oxford?

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Chris came and gave a talk. Chris was at CERN by then, came and gave a talk here.

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That was the first time that I heard anybody from outside Oxford mentioned these things,

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but he had sort of the Oxford contamination, so it wasn't totally clear whether that was independent.

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There were a few people around the world, Feynman and Henry in the States, Lipkins Group in the Institute.

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But that was about it.

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Well, in 1968, Gell-Mann himself came through and he gave a talk at the Rutherford Lab, I think, on the way to the Vienna conference.

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And I thought, well, I will ask him the question, are these things real or not?

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And I desperately wanted him to say that they were. And so what he said is burned on my mind.

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And he said, the quark model is a convenient way for keeping track of the group theory labels and whatever he may have said subsequent to that,

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I have never forgotten that remark that he made to me. I think he made stronger remarks of good George VI, but that's another matter.

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So I was rather depressed. Then what happened was a great experimental breakthrough, a phenomenon known as Bjork in scaling.

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That's the one pun in the Talk, which was a direct experiment done initially in Stanford and then with neutrinos at CERN,

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which showed that there were indeed seeds inside the proton which had the properties of quarks.

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That is what the history says. But it's interesting, actually, to go back.

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I mean, this is 1968 when this all sort of becomes clear.

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But go back the year before in 1967, before Cain himself was describing these ideas at a conference in Stamford,

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and it's obvious that nobody really took them seriously.

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These quotes Bjork An additional data are necessary and very welcome in order to completely destroy the picture of elementary constituents, he says.

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And then the proceedings show Kurt Gottfried the students there's a summer.

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All the Gottfried Sommer is used to establish nowadays that these things are there, Gottfried says.

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I also want to ask a question. I think Professor Bjorklund and I constructed the some rules in the hope of destroying the quant model.

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And then perhaps one of the experts, perhaps Professor Dalits, would care to say how he would view a gross violation of the lecture production.

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Some rules. So you turn to the next page for Dick's response, and there it is.

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So that was the situation.

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Quarks, I think, at least in my perspective from here, really became alive by the fact that Dick had attracted some good postdocs to this institution,

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in particular Gabriel, Carl, Les Copley and Edward Brick.

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And in 1969, they wrote a celebrated paper on what happens when you photo excites some of these resonances that Dick had been talking about.

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And their paper was unusual in that it calculated successfully over 100 different quantum amplitudes are exciting,

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these resonances in relative magnitudes and even their phases, which required some sort of explanation.

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And this was so impressive that Feynman himself took it up. And by 1971, Feynman with two students, Christopher and Ravinder.

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At the end of his career, Feynman was working on this model, and it was the real work that I think probably established the.

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Model as a serious venture on people's minds, whereas in actual fact their work was predicated on the company calling brick,

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which in turn was predicated upon the fact that Dick had brought them here in the first place.

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So what was it that these three guys had done and why was it significant?

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Well, I said, you know, Dick had said in 1964,

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you start off with your your life is state and you can excite one or two levels up and you find bumps, one or two levels up.

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And so these guys used Dick's picture to ask what happens when a photon excites a proton into these various states?

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The data has something very interesting in it.

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It turned out that at a certain configuration, the amplitudes disappeared totally, and this came out of their quantitative calculation.

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Basically what was going on is a photon is an electromagnetic wave.

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The electric field and the magnetic field can both excite the resonance.

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And it happens that in the model. These two destroyed each other for these two particular resonances, which was a remarkable result.

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And that looked to be a very clean idea that the quantum model must be right.

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The problem was that the likes of Gell-Mann would turn around and say, Well,

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actually all you're really doing is playing around with Gordon coefficients from your group theory and fixing it so that this happens,

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which could have been true. But then I was at Slack and Fred Gilman asked the critical question,

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which is what happens when you go from photo production to electron production, or in the jargon, when you vary the mass of the photon?

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And the answer is you're changing the relative amounts of the electric and magnetic field.

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So the cancellation that happens for real photons disappears and it turns out disappears in a very dramatic way,

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which the experiments within a couple of years have confirmed.

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And the key physics of it is that if quarks are real things, when you tickle them slightly by varying from real photons,

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the magnetic response, first of all, grows before it dies away.

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That is exactly what you now see in the data that is showing to me that quarks are real

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objects that are responding to electromagnetic field that far more than just group theory.

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And so the constituent quarks became real.

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I left slack. I came back here and gave a talk.

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And these I found when I was at the Dick's house, we were going through all of his papers a month or two ago,

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and he has this wonderful file with all the notes,

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if you ever saw him in seminars, always writing the notes down in his beautiful writing, he filed them all afterwards.

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So I went to see and I found it. And that was his notes of my 1973 seminar.

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And the amazing thing to me is that that was written in real time, not for written up afterwards, and that was typically Dix seminar notes.

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And so constituent quarks, as we now call them, had become real the following year.

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They became real for everybody because there was this wonderful discovery of the beginnings of the world of charged particles.

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And although Dick himself didn't work directly on that down,

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let's plotz were indeed critical in the discovery of the charged particles which established all of the modern physics, you might say.

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So with quarks established Dick in 97, in 1977, with with Ron Horgan and Reinders extended this idea not just one and two,

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but now with enough data to establish the third excitation in this picture.

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He wrote a couple of other papers, as far as I'm aware, and Ron may know better than I.

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He actually produced very few papers in peer reviewed literature on the model,

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and I think this probably is pretty well the sum total of the papers that he wrote with Ron.

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I then got the final surprise, the final paper that he wrote on the light quark model.

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I hadn't realised that all those years ago. He had actually read my thesis that made two people apart from the examiners it, read it.

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He then produced a paper in 1981 based upon something in it and insisted I put my name on it and I.

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Fair enough. So there it is. And it was his final paper on Hadrons.

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It turns out it went right back to one of the key questions that was lurking behind his 1965 work.

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I don't know whether Chris will mention that or not, but that for me brought the circle around the and a complete circle.

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Dick then turned his interest to the idea of top quarks and how one might investigate those.

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Did a lot of work with Gary Goldstein, about which I don't have the time to tell you today,

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but some of these beautiful artwork and presenting diagrams have had to do that.

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I think if you go and look at their papers in the literature, you will see some beautiful artwork in those as well.

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So to conclude on all this, I will actually quote something from Feynman.

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On this. I mean, for me, the constituent quarks are real things.

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It's just that we still don't know what they actually are. Freiman, collaborator of Mind to advance, told me this,

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that Feynman said this apparently in response to one of Gilman's criticisms after some seminar, the normal sadistic quark model is right.

195
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It describes so many data. It's for theorists to explain why.

196
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So it all started with Dick for me, and I hope that we'll see the picture unveiled later on.

197
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Chris Cornell, for instance, thanks. I do have time for a couple of questions.

198
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Don't rush off right now. Okay. That's right. Well, I would like to, but I will ask you to repeat the question back so that the microphone.

199
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Right. That's fitted for the cameras. Any questions?

200
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Yes. When did the fraction of electrical charge come into this scale?

201
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When did the fractional electrical charge come into this timescale? From almost the very beginning.

202
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Gilman, when he had the idea of of constituents to make the proton, it is somewhat of dispute as to whether he actually realised it,

203
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implied fractional charges or whether I think was it Bob server over a lunch made him realise.

204
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But either way by the time he published his original quark model,

205
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he actually started off with two models, one which had got integer charges but involved four fields.

206
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And then in a footnote he says. However, if you were content with three and were prepared to have fractional charges.

207
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So answer 1964. I remember reading somewhere which he worked out over lunch,

208
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telling you that that if you had a certain condition, you would have to have that to show.

209
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That is, I think, the lunch discussion with with Bob Server story.

210
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Yes, please. The answer is that the first paper on caucuses by paper, he wrote it in French.

211
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It's called obscure title. He was not published for a long time.

212
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He never thought up proofs as a paper of his.

213
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That has a footnote from Elsevier from north of the six letters saying the proof wasn't returned for seven years.

214
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That's why there's a delay. He never.

215
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But before both Zweig and Gelman and he says near the back, if you take these things seriously, of course they've got to have an integral charge.

216
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He said It's a bit strange, but I don't know any fundamental reason why that would be wrong.

217
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And this paper has been completely ignored. Hmm. I only heard about it two years ago.

218
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Just sorry.

219
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Yes. Just an observation. That is what the idea was mooted and discussed among nothing serious.

220
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Then one drew attention to the fact that James Joyce's original words were just three books.

221
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He hasn't got any of the plaque he has is all beside the mark and people like that very much and were already prejudiced against accepting the idea.

222
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I just thought I would put in that little comment on write for a horrible moment if you're going to have a discussion on how we pronounce the word.

223
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But I will not enter the BBC straight.

224
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And at some point you don't it? Well, the question, although it's three quarks of Mr. Mark courts of Alex, Mr. Mark was a was a publican.

225
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So you think it's cork. But actually if you speak with a Dublin accent, it comes out as Quark.

226
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That's the sum total of my erudition on that. Sorry. Anything else?

227
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Well, Chris takes a while to think, because I think since Chris has managed to get hold of the microphone, his time trying to figure.

228
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But Chris doesn't need any introduction either. But I'll say a few words about him too.

229
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For those of you who are new here. So Chris actually predates Frank.

230
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I think he did. Is he with take in 67? There you go.

231
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And that new college, if my detective work is correct.

232
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Yes. Following which she, in fact, did something unusual,

233
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leave it to the level of institute in Moscow and then to CERN and then to Slack, or maybe in the opposite order.

234
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Before he came here in was it 70 but says yes, 74.

235
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So I've got that right. But what I cannot remember are all the things that he did since.

236
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I know, but I get that right. So. So, in fact, as many of us know, because we did unify the different departments of physics into what.

237
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And was the first chairman of physics from 1983 87 to 92 before after which he went to CERN and was the director

238
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general there from 94 to 98 and subsequently has held a string of posts including being Provost of UCL Director of UK.

239
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I think he chaired the Committee for ITER and is continues his energy research interests.

240
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He's the Director of Energy Research at Oxford and also President of the System Council.

241
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That being the machine in the UK but in a somewhat troubled region at the moment.

242
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I should also say that he was awarded the Glazebrook Prize of the IAP in 1999 and the Royal Medal of the Royal Society last year.

243
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But today we are going to hear about Chris's reminiscences of Douglas.

244
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Thanks very much, Bill. So, Dick, it's a great pleasure as well to start as family, friends, colleagues.

245
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Ladies and gentlemen, it's a great pleasure to have this opportunity to pay tribute to Dick again.

246
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Dick was born in Dimboola in the west of the states of Victoria and Wales, just north.

247
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It's just north of the Grampian Mountains. These are the these are the Australian Grampians.

248
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So think gum trees, not pine trees. But his family moved to Melbourne when he was two.

249
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Dick knew that his paternal ancestors came from Germany and they thought they were German.

250
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Then he was called Fritzy for this reason at school, but he was always a bit sceptical about this because he thought the name was a bit unusual.

251
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And it was only when later when he was in Oxford, he discovered they weren't German at all.

252
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Actually, from a preacher, manic inhabitants of what became Brandenburg, a group called the Serbs or Wens, who speak a Slavic language.

253
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And he traced down Jerry Stone as Jerry here.

254
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Apparently not. Who is the leading expert on the swords in the UK?

255
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With him identified in fact the exact village in which his four balls bears came from.

256
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Someone had Leipzig and went there and he met the village historian who turned out to be a distant relative.

257
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And he he did quite a lot of work on the Serbian diaspora.

258
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And actually, in the words of Jerry Stone, in a note published in The Guardian after Dix death,

259
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said Dix Curiosity led him to cast new light on aspects of one history.

260
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But his gift to the land of his father's father was the distinction he brought to the one dish named Dalits.

261
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Now, my qualifications for giving this talk that I was student and then I was this colleague until the 93.

262
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I actually wasn't in Oxford. I was at CERN putting together the proposal for the LHC.

263
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And the third qualification is that within of Aitchison,

264
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I'm writing a memoir of Dick for the Royal Society and I'll explain later why it's taken us ten years, that memoir.

265
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Well, I'm going to begin by quoting the abstract of that memoir, a draft of our memoir.

266
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It's going to be a rather wordy talk, I'm afraid. I'm like francs, but it's the words are mostly going to be dicks.

267
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This slide is an exception. So this gives you a feeling for the things he did.

268
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As a theoretical physicist,

269
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the principle contributions were intimately connected to some of the major breakthroughs of the 20th century in particle nuclear physics.

270
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His formulation of the future puzzle, and I'll say more about that, led to the discovery that parity is not a symmetry of nature.

271
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The first of the assumed spacetime surgeries to fail. He pioneered the theoretical study of hyper nuclei of strange baryon record resonances.

272
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Baryon spectroscopy gave him a model at a time when many considered it naive to all of which he made lasting contributions.

273
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The Plot. The pairs are part of the vocabulary of particle physics.

274
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He remained throughout his career in close touch with many experimentalists, and he had an encyclopaedic knowledge of the data.

275
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Many of his papers were stimulated by experimental results and were concerned with our analysis and interpretation work,

276
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which often required the forging and new phenomenological tools.

277
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Many also indicated. What do experiments need to be done as a consequence?

278
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He was a theorist, exceptionally valued by experimentalists.

279
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He served on a number of scientific boards and committees, including the CERN Scientific Policy Committee,

280
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and he created and ran a strong and flourishing particle group in Oxford.

281
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Now what to choose from this menu. These I'm going to go through these things.

282
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Frank has talked about quarks and that was great that he agreed to do that because that's first of all, I've worked on quarks.

283
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But what Frank has done is closer, I think, to the sort of work addicted but doesn't necessarily agree.

284
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I'll give you a quote of what Frank thought of Dick later. That is on the record his opinion of Frank.

285
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And we haven't, but that's the one part of our memoir we haven't written.

286
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And one of the difficulties is the index list of publications.

287
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I've forgotten the numbers, about 250 publications that are about over 50 that are obviously something to do with quarks.

288
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But there are only 11 in peer reviewed journals, and five of those are with Gary Goldstein.

289
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Most of what he did was published in conferences and and some of them very obscure.

290
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Some are schools. And all these things have been archived. All I can't get hold of them.

291
00:31:03,540 --> 00:31:10,920
So for anybody who has any Dick's papers, particularly conference proceedings, please let me have copies.

292
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Now, I think I'm going to, before I get into the science, go back to his biography.

293
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So he got a first class degree in maths from Melbourne and then a first class degree in physics.

294
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And in 1946, two key things happened.

295
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He married Valda in August 1946 and they moved to Cambridge with a scholarship funded by the University of Melbourne.

296
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But then after a couple of years, in Dix words, I run out of money.

297
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We had a young child by that time, so I took up a one year post in Bristol.

298
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In Bristol, he interacted a lot with the cosmic ray physicist, but after that he moved to Birmingham, where he was strongly influenced by Rudi Pyles.

299
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Now, when Dick became a fellow of the Royal Society in 1960, he was asked to write a memoir of the scientific influences and his background.

300
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And I have the original thing that he wrote, and this is what he said about Rudi.

301
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He said Professor Pyles showed a stimulating enthusiasm for the questions of interest to me,

302
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and discussions with him showed me a viewpoint towards physics, which I found refreshing and novel in the group.

303
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There was also Freeman Dyson. Dyson's famous work on electrodynamics was done in the US,

304
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but it was on a scholarship that obliged him to come back to the UK for two years and he said the only place to be is with piles in Birmingham.

305
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And Dick writes. The presence during those years of Freeman Dyson was especially fortunate for me,

306
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so he gave the first clear lectures on field theory and electrodynamics that I'd heard, and I'll come back to the consequences of that in a minute.

307
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While he was in Birmingham completed his thesis, which I'm going to discuss using these techniques of Dyson's.

308
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Formerly, his Cambridge supervisor was a comer, but actually in his notes for the Royal Society, he never mentioned that comer.

309
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And I think in a minute you'll see why. So I was once trying to trace my scientific ancestry back through Dalits and camera, and I thought I knew it.

310
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And I went to Rudi Pyles.

311
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And suppose I write in thinking that Kammer was supervised by Pauli, who was supervised by Sommerfeld, and Rudy said, Why do you want to know?

312
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And I said, Well, I want to know if, like most theoretical physicists in Europe at that time, I was descended from Sommerfeld,

313
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and he looked at me and said, Everything you said was literally correct, but everything he learned from me.

314
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And then in a typical Rudy way, he smiled and he shook his head.

315
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And he said, he said. But the conclusion is the same because I was taught by Sommerfeld.

316
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Dick then went to Cornell, where he worked in the group of hands, but better who,

317
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in words of a 2003 interview, Dix said, was a tremendous stimulation.

318
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He moved on to Chicago. It was two years after Fermi died and a number of the leading people Gelman Goldberg had left providing,

319
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and I quote Dick again, a tremendous opportunity to build up groups and get things going.

320
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I enjoyed Chicago. I thought it a very interesting place and a very fine university.

321
00:34:25,290 --> 00:34:29,189
Although the place wasn't fashionable with American physicists who tended to go to the East

322
00:34:29,190 --> 00:34:37,769
Coast or the West Coast after Rudy Pyles accepted the Wickham Professorship early in 1962,

323
00:34:37,770 --> 00:34:47,430
although he didn't come to 63, he persuaded to join him at Oxford in 1963, initially on a trial basis with the option of returning to Chicago.

324
00:34:48,390 --> 00:34:50,100
But the very beginning,

325
00:34:50,400 --> 00:34:58,080
Dick was a consultant to the Science Research Council and to the high energy physics group at what was then known as the Rutherford High Energy Lab.

326
00:34:58,080 --> 00:35:01,800
And I'm glad to see people from there here today.

327
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Dick described this as a happy arrangement. He selected the first bunch of arrays Pasha Picabia, Chris, Michael Grimshaw, Sian Low,

328
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and he also recruited Roger Phillips, who is here today as the head of the group, although just tells me.

329
00:35:18,030 --> 00:35:26,850
But Dex said to him that I wasn't his dick's first choice and disarmingly told him who all the competition was, who turned the job done.

330
00:35:29,010 --> 00:35:34,290
Dick went to all the seminars and he took these meticulous notes of Frank's given us an account of.

331
00:35:34,290 --> 00:35:37,349
But but but they never said very much and as pushed them.

332
00:35:37,350 --> 00:35:44,790
We've seen that also in what you saw at least in the open sessions that he went to it, the particle physics collect selection panel.

333
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I'm going to come back to some reminiscences of Dick's time at Oxford at the end of this talk.

334
00:35:51,870 --> 00:36:00,359
Now, I think there are a few students here, so I'll just give a bit of context to try and put ourselves back in the mind of what it was like.

335
00:36:00,360 --> 00:36:06,240
And I'll take two snapshots of the year that Dick came to the UK of the year he came to Oxford.

336
00:36:06,870 --> 00:36:10,709
So in 1946, the elementary particles with a proton, the neutron,

337
00:36:10,710 --> 00:36:17,310
an electron and a cosmic ray meson known to have a mass about 200 times that of the electron of the electron.

338
00:36:17,940 --> 00:36:24,210
Perhaps the particle predicted by Yukawa and the neutrino have been postulated, but of course not seen.

339
00:36:24,600 --> 00:36:27,750
1947. It turned out those were actually two particles.

340
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By 1963, here were the elementary particles, the leptons, by the way, the world.

341
00:36:35,490 --> 00:36:40,680
The word meson was invented in 1939, the word lepton in 1947.

342
00:36:40,680 --> 00:36:51,360
So it doesn't exist. When it came to the UK Hadron in 1962 and Baryon in 1954, the baryons written there the mesons at a small number of resonances.

343
00:36:51,360 --> 00:36:58,500
And as Frank told us, many of them discovered with all plots the Rho Omega Eater and K Star all in the one year in 1961.

344
00:36:59,790 --> 00:37:06,960
Now, what about theory? In those days it was generally felt that the field theory just wasn't going to work for the strong interactions.

345
00:37:07,230 --> 00:37:10,840
And everybody was talking about self-consistent bootstrap theories.

346
00:37:10,860 --> 00:37:11,790
That was the language.

347
00:37:12,270 --> 00:37:20,879
The high priest of all this was Geoffrey Chu, who was on record as saying field theory like an old soldier will not die, but simply fade away.

348
00:37:20,880 --> 00:37:26,520
So we were encouraged. Don't think about field theory, what Dick said, learn the refinement rules and calculate.

349
00:37:26,520 --> 00:37:31,860
But don't take field theory. He didn't say that. But the other theory said that.

350
00:37:32,190 --> 00:37:37,140
But what is this bootstrap theory? That's just the idea. So the students here if you have.

351
00:37:37,420 --> 00:37:44,350
Say Pie, pie scattering. And you imagine there's something exchanged here,

352
00:37:44,680 --> 00:37:53,260
maybe with someone that creates a potential and as a result of that force, that could perhaps generate something.

353
00:37:53,820 --> 00:37:57,940
You see that by far in this direction, which would be the same thing.

354
00:37:57,950 --> 00:38:03,640
So the idea is you hypothesise a particle and then a self-consistent way it would invent itself.

355
00:38:05,110 --> 00:38:09,280
Now, that was the idea, and that's what people were working on.

356
00:38:09,280 --> 00:38:14,890
And I will come back to that a little bit later. But for now, let me go back to the two pairs.

357
00:38:15,670 --> 00:38:19,990
So Dick's thesis was on zero zero transitions in nuclei.

358
00:38:20,260 --> 00:38:23,469
So this is an excited oxygen 16.

359
00:38:23,470 --> 00:38:29,590
He started inspired by some experiments by some doesn't require this came to the grand state.

360
00:38:29,740 --> 00:38:39,340
So for the non physicists the grand state this is a state of 16 nuclei, neutrons and protons arranged in the most stable possible configuration.

361
00:38:39,820 --> 00:38:44,110
But there can be other configurations for that moving or arranged differently, which have higher energy.

362
00:38:44,410 --> 00:38:45,400
And that's the state.

363
00:38:45,730 --> 00:38:53,530
This with a star on it is 6 million electron volts above the grand state and this excited state wants to get back to the grand state.

364
00:38:53,530 --> 00:38:56,860
So something's got to take up the energy for it to get back there.

365
00:38:57,130 --> 00:39:00,670
And the obvious thing would be a photon, but that's a particle of light.

366
00:39:00,970 --> 00:39:05,200
That's impossible because the photon is spinning and the oxygen nuclei not spinning.

367
00:39:06,070 --> 00:39:09,160
But Dick, it was realised not by Dick,

368
00:39:09,160 --> 00:39:16,150
but that that you can go through what's called a virtual photon and go into an electron positron pair which can take,

369
00:39:16,390 --> 00:39:27,430
which can be not even but that spin works out. And he calculated that in his thesis and he says in his thesis he acknowledges his debt to

370
00:39:27,430 --> 00:39:33,310
the lectures of Mr. Dyson and thank Professor Pyles for his continued interest in this work.

371
00:39:34,750 --> 00:39:40,000
In 1951, Dick had moved to Birmingham by then,

372
00:39:40,000 --> 00:39:47,829
but he was going back to Bristol periodically and he went back one weekend to visit some friends, I think in the north, in southern Europe.

373
00:39:47,830 --> 00:39:55,660
And in those days, Felder and he, the friend said to him, here are two peculiar pairs that they'd seen.

374
00:39:56,200 --> 00:40:00,960
In each of these cases, the outgoing pair of tracks were clearly identified as electronic.

375
00:40:00,970 --> 00:40:08,260
What was peculiar about them was the origin of each pair could not be seen as separate from the centre of the cosmic red star from which it emerged.

376
00:40:08,500 --> 00:40:12,190
What could give rise to these pairs? On my way back to Birmingham,

377
00:40:12,190 --> 00:40:17,829
I suddenly realised that the pi zero itself could rise to them by direct decay to gamma e

378
00:40:17,830 --> 00:40:22,809
plus minus through the process of internal power conversion of one of its product photons.

379
00:40:22,810 --> 00:40:27,970
So the pi zero goes to two photons, one is virtual, one converts to B plus A minus.

380
00:40:28,210 --> 00:40:38,920
And these, of course, are its pairs. Now, Dick, he recording his thesis work, calculated the right.

381
00:40:38,920 --> 00:40:41,080
This is the same note for internal conversion.

382
00:40:41,090 --> 00:40:49,570
So this is a same calculation as his thesis in a different context and found a branching ratio of 1.185%.

383
00:40:49,990 --> 00:40:56,230
When you put in more complicated calculations at times into 1.195, very close to today's value.

384
00:40:57,460 --> 00:41:00,430
Now, Dick knew that this had to be right and he wanted to publish it.

385
00:41:00,910 --> 00:41:05,140
And he said to the Bristol people, Why did you publish this paper in parallel with me?

386
00:41:05,830 --> 00:41:12,310
But they said with two events we don't want to claim a discovery, and he couldn't persuade them to publish.

387
00:41:12,550 --> 00:41:15,010
And he's in a 1987 interview.

388
00:41:15,280 --> 00:41:23,440
Listen, all you experimenters in the room, Dick, writes, You don't see many experimenters around today with such high standards for publication.

389
00:41:24,910 --> 00:41:36,360
I like that dotted pairs prove to be a very useful tool for the finding the the parity brothers of Parity of Sigma and Lambda.

390
00:41:36,640 --> 00:41:40,030
The also for measuring the power of the pi zero.

391
00:41:40,030 --> 00:41:45,670
And I leave it to the students to figure out how that's done. Now let's come to the talk later puzzle.

392
00:41:46,780 --> 00:41:54,280
So Dick was much influenced by a conference Oral Society discussion meeting of particles in January of

393
00:41:54,280 --> 00:42:04,959
1953 at the Royal Society and upper level events were shown the case for what's called the top plus,

394
00:42:04,960 --> 00:42:08,620
now called K plus into pi plus pi minus three pi mana.

395
00:42:08,620 --> 00:42:11,890
So this is a heavier particle, the k into three lighter particles.

396
00:42:12,580 --> 00:42:18,250
And Dick later recalled the time was right to give some serious consideration to their characteristics.

397
00:42:19,120 --> 00:42:22,899
And he went away and gave that serious consideration and wrote a paper.

398
00:42:22,900 --> 00:42:34,240
Submitted the paper, but before it was published, he went to the famous conference July 1953 in Barnier, the Beagle in the in the French Pyrenees.

399
00:42:35,170 --> 00:42:38,319
Now, that was a watershed in particle. Physics Conference.

400
00:42:38,320 --> 00:42:45,760
It was the last conference which the data came entirely from cosmic rays, and then it was taken over after that by accelerators.

401
00:42:46,120 --> 00:42:52,590
Dick himself felt, and I quote, It was a major event in the lives of all the physicists who took part in it.

402
00:42:53,440 --> 00:42:58,990
And Jim Cronin has written a historical account of the conference You Can't Be There Actually is Too Young.

403
00:42:59,380 --> 00:43:01,810
It's subtitled The Birth of Subatomic Physics,

404
00:43:01,810 --> 00:43:08,860
and he places it in the same category as the 1927 Solvay Conference and the 1947 Shelter Island Conference.

405
00:43:09,640 --> 00:43:14,140
Now, I know that Don Perkins, who's here somewhere. I've lost your Dom here, was there.

406
00:43:14,320 --> 00:43:18,490
And you told me you got bored and you and Dick went off hiking in the Pyrenees.

407
00:43:19,000 --> 00:43:25,390
And you also told me a very nice story that that was some sort of bench separating the audience from the speakers.

408
00:43:25,690 --> 00:43:34,090
And one of the chairmen was La Presse, Frank de la Presse, who brought with him a wind up tin monkey,

409
00:43:34,240 --> 00:43:37,960
which, if you let it go, would walk dragging a drum like this.

410
00:43:38,260 --> 00:43:41,800
And he put it on the end of the desk and he said to the speakers in the session,

411
00:43:41,980 --> 00:43:48,190
If any of you go over time, I'll let this market go and that get them kept them on time.

412
00:43:49,570 --> 00:43:56,080
By then the tower was well established and known to have a mass 970 plus or minus five times the mass of the electron.

413
00:43:56,380 --> 00:44:01,180
And at that conference, a new discovery was reported, a particle called Theta.

414
00:44:01,180 --> 00:44:07,810
Then 9:00 zero two came to two PI's with almost the same well, but then the Aras the same mass.

415
00:44:08,320 --> 00:44:14,710
And the question immediately was, are these twins, brothers or sisters of each other, or are they independent?

416
00:44:15,340 --> 00:44:20,170
Are they different? If they were the same particle, different charge states.

417
00:44:20,380 --> 00:44:24,790
They would have to have the same speed and parity. Also something about what parity is a minute.

418
00:44:25,720 --> 00:44:33,730
Now, Dick's analysis showed when enough events should be plural had accumulated that the pi plus pi minus

419
00:44:33,910 --> 00:44:42,310
the state from pi zero decay and the three pi state from tau path decay have different parity,

420
00:44:43,090 --> 00:44:49,330
which meant that either parity mirror's symmetry is not conserved, which is a totally revolutionary idea at the time.

421
00:44:49,630 --> 00:44:56,140
And I'll come back a little bit to that. Or some unknown symmetry produces states with the same mass but opposite parity.

422
00:44:56,140 --> 00:45:01,000
I've lost a word that now the its plot.

423
00:45:01,180 --> 00:45:08,770
So Dick later recalled of I'm not to read these words let the physicists read them and I'll try and explain them a bit to other people.

424
00:45:09,130 --> 00:45:16,870
Dick realised that when you have one particle decaying into three, the table into three pies, the question is how do they share the energy?

425
00:45:17,170 --> 00:45:21,100
Does all the energy go into kinetic energy? And two and the third's at rest.

426
00:45:21,760 --> 00:45:25,210
Do they share it equally? What are the angular distribution between them?

427
00:45:26,050 --> 00:45:30,670
And Dick realised that without having any fundamental knowledge of how this worked,

428
00:45:30,910 --> 00:45:37,300
you could find a way of looking at the data in which you could figure out from how the energy was shared,

429
00:45:37,600 --> 00:45:43,240
what were the properties of the primary type. Plus, this would give a clue to what his priority was.

430
00:45:43,900 --> 00:45:49,420
So here's a lot of words saying what I said in a slightly more professional way, but then it ends.

431
00:45:49,420 --> 00:45:56,230
First representation was needed to display the distribution of the events pictorially, and here it is.

432
00:45:56,980 --> 00:46:02,130
There was always a bit embarrassed because everyone else is talking about the plot and he didn't want it.

433
00:46:02,140 --> 00:46:06,910
He'd never use the word first of its part, he said, the familiar plot, the phase based plot.

434
00:46:07,120 --> 00:46:10,660
He'd find some way around using his own name here.

435
00:46:12,670 --> 00:46:23,380
Anyway, if you have a X going to A plus B plus C, the sums of the energies has to add up to the fixed total energy of the rest mass of the x.

436
00:46:23,650 --> 00:46:27,460
And the question is how to treat A, B, and C on an equal footing.

437
00:46:28,450 --> 00:46:33,790
And Dick remembered from his geometry. He'd learned a school to learn a triangle.

438
00:46:34,000 --> 00:46:36,760
If you put any point in the middle of this triangle,

439
00:46:37,990 --> 00:46:45,640
then the perpendicular distances to the each side add up to a fixed amount wherever it is in this triangle.

440
00:46:46,360 --> 00:46:52,930
So you could put a plot here which showed simultaneously the energy of a is the distance from one side.

441
00:46:52,950 --> 00:46:57,850
The energy B is a distance from the other and the other. You see from the distance a third.

442
00:46:58,060 --> 00:47:03,460
So you could treat them all on absolutely equal footing. And this is the plot from the paper.

443
00:47:04,240 --> 00:47:13,090
And the other point about this is that the distribution of plot here directly relates to physics with no kinematic factors, equal areas,

444
00:47:13,090 --> 00:47:22,360
equal face space for the for the physicists as they accumulated, the events populated the climatically alive domain that's inside the circle.

445
00:47:22,690 --> 00:47:29,890
If you put in relativity, it's not quite a circle anymore, uniformly, which showed there's no relative angular momentum.

446
00:47:31,360 --> 00:47:35,890
And in fact, the parity of the title has to be opposite of that of the feature.

447
00:47:36,990 --> 00:47:41,130
Let me say a little bit about mirror symmetry for the non physicists in the room.

448
00:47:41,670 --> 00:47:51,450
Until this date it was assumed that nature was mirror symmetric, which means if you took a film of something, an experiment,

449
00:47:52,260 --> 00:47:59,309
it would be impossible to tell if that film was shot directly or it was a film of a mirror reflecting the experiment.

450
00:47:59,310 --> 00:48:04,400
There was no experiment that could tell you, Is this a direct film or a film in the mirror?

451
00:48:04,410 --> 00:48:08,930
Impossible. Of course, in the real world you would see writing was going the wrong way, wrong.

452
00:48:08,940 --> 00:48:12,030
But we could imagine a civilisation which wrote the wrong way wrong.

453
00:48:12,360 --> 00:48:17,700
It was absolutely impossible. And this was regarded as a totally fundamental principle of physics.

454
00:48:18,240 --> 00:48:21,729
So this discovery, but these things had opposite parity.

455
00:48:21,730 --> 00:48:24,990
It was really quite hard to take and this is what Dick said.

456
00:48:25,380 --> 00:48:31,830
How is it possible that reflection and variance this is this mirror symmetry should not hold people lost was

457
00:48:31,830 --> 00:48:38,160
not left right invariance inherent in most our most fundamental conceptions about safe time space time.

458
00:48:38,550 --> 00:48:42,900
The only answer available was the occurrence of both K2 Pi and K2 three.

459
00:48:42,900 --> 00:48:48,600
Pi decays actually did demonstrate this, i.e. that there was a breaking of the symmetry,

460
00:48:48,600 --> 00:48:56,430
but this answer did not have compelling force because it could not point to any explicit empirical demonstration of parity of failure.

461
00:48:56,640 --> 00:48:59,940
This particular experiment, you could look at it in the mirror and you couldn't.

462
00:49:00,120 --> 00:49:06,149
It would look the same in a mirror. It required less faith to suppose that there existed.

463
00:49:06,150 --> 00:49:13,110
Two distinct came as on charge doublets called feature and total close in mass but with different spin parities.

464
00:49:13,320 --> 00:49:17,969
The mental obstacle to accepting the parity violation explanation arose from the fact

465
00:49:17,970 --> 00:49:22,500
that total feature puzzle did not provide an explicit demonstration of parity violation.

466
00:49:23,310 --> 00:49:29,910
So Dick was going around saying maybe the answer is parity is not conserved, but Rudi Pyles and others said, No, it's impossible.

467
00:49:29,910 --> 00:49:38,940
We know parity is a good symmetry. Probably it was particularly strong on this actually, and it was a genius of Lee and Yang who said, well,

468
00:49:39,120 --> 00:49:44,250
is there any evidence in so-called weak decays of this at the parity is conserved

469
00:49:44,460 --> 00:49:48,390
and they found another process and a totally different class of reactions,

470
00:49:48,390 --> 00:49:55,670
not obviously related, but tonic decays where they pointed out that you could do experiments which would look different.

471
00:49:55,670 --> 00:50:00,030
They formed directly and then the mirror and the answer was parity was not conserved.

472
00:50:00,330 --> 00:50:06,750
And this was a really major, major event in physics. The problem was created by Dick, no question about it.

473
00:50:08,250 --> 00:50:12,510
Now I want to come to some work that Dick did on what are called hyper nuclei.

474
00:50:13,290 --> 00:50:17,820
So what are hyper nuclei? Ordinary nuclei consist of protons and neutrons.

475
00:50:18,360 --> 00:50:26,970
Hyper nuclei, one of the protons and neutrons, or maybe more actually is replaced by what's called a strange particle.

476
00:50:27,150 --> 00:50:31,370
This is a particle which, instead of having the familiar up, down goes up.

477
00:50:31,380 --> 00:50:38,370
Don Quarks has a strange quirk in it, if you like. Now, these things have been discovered in 1952,

478
00:50:38,940 --> 00:50:49,770
in a hyper fragment event in a balloon from photographic emulsion in which some nucleus is hit by a k mazen cosmic ray mass v particle.

479
00:50:50,040 --> 00:50:56,660
And it converts one of the ordinary protons and neutrons into a strange baryon and emits a pile.

480
00:50:57,820 --> 00:51:04,649
But in his first paper on the hype a nuclear, by the way, Nick Dick became interested in hyper nuclei.

481
00:51:04,650 --> 00:51:13,290
His interest was arise by Lucado, Leavitt, Levi Ceti, a colleague in Chicago, and Dick has written later, we each benefited from each other.

482
00:51:13,290 --> 00:51:17,999
I think we got quite a lot done. It's a fantastic understatement.

483
00:51:18,000 --> 00:51:21,570
He was the leader in this field for the rest of his career.

484
00:51:22,710 --> 00:51:30,120
The first paper he showed that the fact that these two nuclei, the one on the left for Lambda H,

485
00:51:30,190 --> 00:51:34,950
such a thing with one proton, two neutrons and one lambda particle.

486
00:51:35,730 --> 00:51:39,480
The other one, which is two protons, one neutral and one lambda particle,

487
00:51:39,660 --> 00:51:45,750
have almost the same mass Dicke used that to show that the force between the lambda and the proton,

488
00:51:46,080 --> 00:51:50,340
between the lambda and the proton and the lambda and the neutron have to be the same,

489
00:51:50,940 --> 00:51:55,230
which nobody knew any way of measuring that until he figured that out.

490
00:51:56,490 --> 00:52:00,569
Now, he then went on to do a lot of other things and I'm not going to go through this.

491
00:52:00,570 --> 00:52:06,180
I will leave the physicist to read the rest of this, the rest of the side slide.

492
00:52:06,420 --> 00:52:13,380
Except to say that Dick once hinted to me that he actually saw his work on hyper nuclei as a bit of a chore.

493
00:52:14,220 --> 00:52:19,950
He was one of very few, but by far the best theorists who took any interest in the hyper nuclei.

494
00:52:20,460 --> 00:52:23,840
Although later he had a really excellent collaborator, Avraham Go.

495
00:52:24,740 --> 00:52:30,270
The experimenters came to him with that data and say, I've measured this, help me explain it.

496
00:52:30,480 --> 00:52:35,129
And they had a tremendous sense of obligation. So he went on working on hyper nuclei.

497
00:52:35,130 --> 00:52:36,030
But I can remember.

498
00:52:36,940 --> 00:52:44,770
The occasion outside the Headquarters Auditorium, 1968, where he hinted to me that he slightly regretted that he was trapped in working on this.

499
00:52:45,010 --> 00:52:49,750
But he did a fantastic series of things, as you can read here.

500
00:52:50,080 --> 00:52:56,920
And I think some of this he really made it tremendously skilful in working on systems with small numbers of filming on some of them,

501
00:52:57,340 --> 00:53:03,060
which he put to very, very good use later in his work on the cork model.

502
00:53:04,660 --> 00:53:14,469
The last scientific topic before I come to some personal reminiscences concerns Dick's work on carry on nuclear interactions C,

503
00:53:14,470 --> 00:53:18,820
D, D Poles and a K matrix. So I think there are some students here.

504
00:53:18,820 --> 00:53:23,530
I think so I'll be a bit of pedagogical because you've probably never heard of a K matrix anymore.

505
00:53:24,220 --> 00:53:32,980
So if you look at the scattering matrix, you can write it as one minus I k another matrix over two to just a convention divided

506
00:53:32,980 --> 00:53:38,530
by one plus I k over two and then you a thority the fact that probability is conserved,

507
00:53:39,430 --> 00:53:44,110
which requires this condition that I've written here forces k to be emission.

508
00:53:45,100 --> 00:53:52,210
But if time reversal is a good symmetry, which it is in strong interactions, then K has to be real case symmetric.

509
00:53:52,660 --> 00:53:54,340
So I think was one of the first.

510
00:53:54,400 --> 00:54:00,729
The K metrics have been used in potential scattering, but Dick was the first person to use it in relativistic situations,

511
00:54:00,730 --> 00:54:04,150
in multichannel situations, and he realised it was a very,

512
00:54:04,150 --> 00:54:10,870
very good way parameters in the data because a couple of parameters for a simple symmetric

513
00:54:10,870 --> 00:54:15,280
matrix and you automatically have these nice properties of unitary seven to it.

514
00:54:16,570 --> 00:54:21,070
The other thing I think I've got to say something about CD polls because many of you,

515
00:54:21,700 --> 00:54:26,500
even most people of my age, we remember the word, but we don't necessarily remember what they were.

516
00:54:27,250 --> 00:54:34,959
Now, if you put the scattering matrix as a unit matrix, plus i t t as an analytic function,

517
00:54:34,960 --> 00:54:38,110
apart from certain cuts, I'm going to be a little bit technical for a minute.

518
00:54:39,100 --> 00:54:55,860
You can set T equals an over D and that was a tool that was used in the 1950s for studying bootstrap models and also for solving model field theories.

519
00:54:55,870 --> 00:55:03,070
I think it was first introduced looking at the true low model and in the nanobody model,

520
00:55:03,310 --> 00:55:09,610
the end function is analytic apart from the left hand cut which reflects particle exchanges or forces.

521
00:55:09,620 --> 00:55:19,689
So in this cut this here, a row being exchanged here would show up as a pole in the the end function and then totality and analytic

522
00:55:19,690 --> 00:55:25,239
city allow you to calculate D and in the bootstrap model you find it had a pole and that was the Roma's.

523
00:55:25,240 --> 00:55:31,600
And again, you'd made it so consistently and the CDP poll is a paper by Castella or Dyson,

524
00:55:31,600 --> 00:55:39,520
and it's in 1956, they pointed out that any solution to the end of a DX equation remains a solution.

525
00:55:39,520 --> 00:55:42,580
If you add a pole today, there's an arbitrariness.

526
00:55:43,450 --> 00:55:48,730
You can solve all the wonderful self-consistent equations and there's always some freedom left over.

527
00:55:49,570 --> 00:55:56,020
And that freedom can give rise to poles in the scattering amplitude sync CCD poles.

528
00:55:56,560 --> 00:56:03,640
And in fact, this is the way an elementary particle would be built in to a formalism that was set up not to have elementary particles,

529
00:56:04,030 --> 00:56:14,919
but to be a bootstrap model. Now, in a series of papers with some food, one of my name familiar to you and Vito and later others started.

530
00:56:14,920 --> 00:56:23,530
In 1959, Dick presented a masterly analysis of K and scattering and developed the relativistic multichannel K matrix formalism.

531
00:56:24,850 --> 00:56:35,499
In the first paper he discovered that in one of the fets there was a pole in the lower half physical complex plane for the experts,

532
00:56:35,500 --> 00:56:40,299
which was something completely unthought of, which is not known to be a particle called the Lambda.

533
00:56:40,300 --> 00:56:45,250
1405 And it says in the paper that was just one of two solutions.

534
00:56:45,250 --> 00:56:49,899
The appearance of appearance of this maximum of correspond to the existence of a resonance in powered

535
00:56:49,900 --> 00:56:57,760
hyper hyper on scattering for a closely related energy value and an increasingly sophisticated analysis.

536
00:56:58,480 --> 00:57:01,299
They refined that idea with different collaborators,

537
00:57:01,300 --> 00:57:09,130
including Roger Zucker and who was quoted earlier by Frank and showed that there had to be such a pole and indeed it was there.

538
00:57:10,570 --> 00:57:16,209
So that was the situation. I guess in something like the seventies it was known that could predicted this particle.

539
00:57:16,210 --> 00:57:22,840
It was there, but it was never quite clear what it was. And he went on worrying about this in the language of the time.

540
00:57:23,170 --> 00:57:27,490
What's it? Another monetary particle, a CG pole, in fact, or composite?

541
00:57:27,880 --> 00:57:31,480
Could it be dynamically generated in this sort of way by meson exchange?

542
00:57:31,480 --> 00:57:35,530
And he wrote a paper with one of his students on that more recently.

543
00:57:35,530 --> 00:57:40,060
You might think it's a three. But it's much lighter than what would normally be its partner.

544
00:57:40,480 --> 00:57:48,430
And this is a bit of a mystery to today and in fact it is a rather weird state and of skews, he suggests maybe it's a can molecule.

545
00:57:50,020 --> 00:57:56,200
Now, I want to finish with a few reminiscences. First of all, on Dick's scientific style.

546
00:57:57,070 --> 00:58:04,630
In the 1960s, when I became Dick student, many leading theories were tried to develop new theories and new models.

547
00:58:05,260 --> 00:58:09,700
So I rather naively said to Dick, What model are you developing?

548
00:58:10,060 --> 00:58:14,500
And he replied, My job is not to make theories, it's to understand the data.

549
00:58:15,260 --> 00:58:16,450
And that was his attitude.

550
00:58:16,840 --> 00:58:26,829
And later, about a year later, I felt very disoriented because the whole class of fashionable theories you twiddle 12, used six, comma six.

551
00:58:26,830 --> 00:58:30,610
This was suppose to combine internal and external symmetries.

552
00:58:31,480 --> 00:58:35,410
It's been done subsequently in supersymmetry, but in the way it was being done.

553
00:58:35,410 --> 00:58:40,450
Then, after huge series by some of the best known physicists in the world pushing for this and

554
00:58:40,450 --> 00:58:44,560
thinking they'd solved the whole the theory of everything that was shown to be inconsistent.

555
00:58:45,370 --> 00:58:52,149
And I said to Dick, it's a bit disconcerting for a student to listen to these great men telling us these things,

556
00:58:52,150 --> 00:58:58,750
and then it's proved it must be wrong. And Dick looked at me, it was just complete incomprehension and just said,

557
00:58:59,110 --> 00:59:04,960
Those who jump on bandwagon Smith's just for spec to fall off wise pieces of advice.

558
00:59:05,380 --> 00:59:06,520
And in the same vein,

559
00:59:06,520 --> 00:59:15,400
Gabriel Karl is been quoted by Frank described to me reporting to Dick a paper that considered the possible effect of a hypothetical interaction.

560
00:59:15,910 --> 00:59:20,740
And Dick looked at him in a puzzled way and said, But there is no such interaction.

561
00:59:21,280 --> 00:59:24,640
And Gabriel said, Yes, if you know how Gabriel speaks.

562
00:59:24,790 --> 00:59:30,490
But you can imagine that such an interaction to which Dick said, in that case, stop yourself.

563
00:59:31,840 --> 00:59:38,650
So very pragmatic. And his own approach was to immerse himself in the data, which he had an encyclopaedic knowledge.

564
00:59:39,250 --> 00:59:46,959
I remember once after him quoting an experimental result for him, and then he was embarrassed.

565
00:59:46,960 --> 00:59:50,290
He apologised. He said, I'm not sure if it's right, I'll have to check it.

566
00:59:50,500 --> 00:59:54,010
And so he got out his meticulous notebooks. Of course it was right.

567
00:59:54,520 --> 00:59:59,829
And then he looked at me. He said, You know, I used to know all the data at one time.

568
00:59:59,830 --> 01:00:01,000
I knew every event.

569
01:00:02,950 --> 01:00:11,680
I think that he saw the theorist role as being to find a way of representing data so that they directly reveal nature secrets, as the plot had done.

570
01:00:13,000 --> 01:00:20,920
If I come to corks, it's hard for anybody who wasn't involved or wasn't there to remember the incredible antagonism.

571
01:00:21,790 --> 01:00:26,529
Dick, of course, and Frank has shown this knew that the supposed behaviour of corks was impossible

572
01:00:26,530 --> 01:00:30,790
to reconcile with then current understanding of our knowledge of forces.

573
01:00:31,030 --> 01:00:39,420
But he was much more impressed by the fact the quote model provides a simple way of of just remembering the data, putting it together first.

574
01:00:39,650 --> 01:00:45,850
Dick didn't put any students to work on. So I guess, Ron, you may have been the only student he asked to work on corks.

575
01:00:45,850 --> 01:00:52,150
I'm not sure, because I think he thought that it might prove a handicap in the careers because

576
01:00:52,240 --> 01:00:55,330
although he thought it was right and most of us came to think it was right,

577
01:00:55,540 --> 01:01:02,320
it was very speculative. And it might have looked like a career handicap probably in the sixties to be working on corks.

578
01:01:02,710 --> 01:01:07,780
I actually thought he'd put Frank to work on corks, but Frank said that wasn't the case.

579
01:01:08,410 --> 01:01:10,780
And here's what Frank Dick thought of Frank.

580
01:01:11,170 --> 01:01:19,450
So I find in the 2003 interview in which Dick was asked, I believe you taught Frank Close, how was Frank as a student?

581
01:01:20,320 --> 01:01:24,060
And the answer is, it says laughs in brackets.

582
01:01:24,370 --> 01:01:31,960
So, so, so, so Dick laughs. And he said, Well, we didn't always agree on things, but I think we're getting closer now.

583
01:01:34,330 --> 01:01:39,430
But prior to that, I did some work on quarks. Thanks, in a sense, to my opposition to Dick.

584
01:01:40,030 --> 01:01:43,540
So at first, as a sort of cocky, self-confident, arrogant student.

585
01:01:43,870 --> 01:01:48,040
I went along with the fashionable view. This quote model must be a little rubbish.

586
01:01:48,040 --> 01:01:49,810
It can't be, can't be right.

587
01:01:50,290 --> 01:01:57,490
And I was particularly impressed by something called the vice called van Rooyen Paradox, which seemed to show an inconsistency in the, quote, model.

588
01:01:57,880 --> 01:02:01,240
And I said to Dick, look, this paper shows what you're doing is inconsistent.

589
01:02:01,240 --> 01:02:08,820
Why don't you give it up? And Dick said to me, I would give it up if somebody could show me how to derive this result relativistic me.

590
01:02:09,280 --> 01:02:14,290
And I thought, that's a great challenge. I will get the famous professor to abandon the quote model.

591
01:02:15,100 --> 01:02:18,110
And I figured out a way to look at it. Relativistic made.

592
01:02:18,130 --> 01:02:21,700
There's a resolution. It's a bit surprising and still not understood today.

593
01:02:21,700 --> 01:02:25,120
It's something to do with the relationship between current and constituent quirks.

594
01:02:26,500 --> 01:02:28,150
So he didn't give up.

595
01:02:29,080 --> 01:02:36,070
But while working on this paradox, I became very versed in the court model and I recall saying to one of my other cocky colleagues.

596
01:02:36,860 --> 01:02:43,530
Crop models, all a load of rubbish, but it's a very good way to remember all the data and then thinking That's a really stupid remark.

597
01:02:43,560 --> 01:02:52,520
What's a good model but a way to remember the data? From that moment I was a believer and I continue to be a believer as early as 1967.

598
01:02:53,000 --> 01:02:59,990
You faced a lot of opposition for years. You had to believe seminars at the Lebedev Institute of Moscow at CERN.

599
01:03:00,620 --> 01:03:04,760
You know, I'm going to talk about the court model. Why are you talking about this post loss?

600
01:03:04,770 --> 01:03:08,660
They said to me in Russian and you had to defend it also at CERN.

601
01:03:08,900 --> 01:03:15,290
And that was the case for about five years until the seventies, when Feynman jumped on this paper,

602
01:03:15,290 --> 01:03:19,699
which was not really very original, and then people somewhat refinements, taking it seriously.

603
01:03:19,700 --> 01:03:25,880
I can take it seriously. And suddenly it became regarded as sort of trivial.

604
01:03:26,810 --> 01:03:33,290
And I think that never got the credit as a result that he should have done, but I don't think he should resentment of that.

605
01:03:34,390 --> 01:03:39,770
Of course, as I've said, it was a wish to understand the data that underlie Dick's interest in quarks,

606
01:03:40,100 --> 01:03:45,620
and I think particularly the new resonances arising from experiments in Nimrod at the Rutherford lab.

607
01:03:46,340 --> 01:03:50,419
And some of us will remember that Dick ran a series of seminars.

608
01:03:50,420 --> 01:03:58,670
They took place at 830 in the evening in the old high school across the road, which is part of the materials department now.

609
01:03:59,390 --> 01:04:02,360
And Dick said There's no other time in the week. It's too full.

610
01:04:02,360 --> 01:04:08,510
We'll have the seminar at 830 in the evening and he would arrive with a series of distinguished speakers,

611
01:04:08,930 --> 01:04:11,000
frequently a little bit late and out of breath.

612
01:04:11,210 --> 01:04:17,090
And generally the speakers in a state of complete bafflement, having been exposed to high, turbulent, all souls.

613
01:04:17,360 --> 01:04:21,890
It was a very alien experience. And then at 830 in the evening, asked to give a talk.

614
01:04:22,520 --> 01:04:27,270
I remember these talks vividly and people showing data and well, it fit the model.

615
01:04:27,290 --> 01:04:30,319
Won't it fit? Some of you are old enough to remember the split.

616
01:04:30,320 --> 01:04:38,960
I to. This was Bogdan Margalit who claimed that the aid to Amazon was actually true Amazon's and that would have been the end of the quote model.

617
01:04:39,230 --> 01:04:42,350
So this evening was really intense. Was this right or wrong?

618
01:04:42,350 --> 01:04:47,570
It was wrong. The data. Now, what did the students think of Dick?

619
01:04:48,140 --> 01:04:52,670
Well, one of his accepted as a Dick student, my undergraduate tutor wrote to me,

620
01:04:52,940 --> 01:04:58,400
Dallas's leader, all you have to do is keep up a very daunting instruction.

621
01:05:00,140 --> 01:05:08,750
Text style soon became clear to us. Within a month or two, we set out to work on calculations immediately relevant to experiments,

622
01:05:09,290 --> 01:05:17,299
and we were impressed and a bit intimidated by his intellect, his knowledge and reputation, and by the way, particularly he'd reflect on the question.

623
01:05:17,300 --> 01:05:20,000
If I ask him a question, then there'd be a long silence.

624
01:05:20,000 --> 01:05:25,220
He wouldn't answer until the you know, even if it was 5 minutes, you'd stand there and you'd think, Did he hear me?

625
01:05:26,120 --> 01:05:30,050
Make some stupid remark out of embarrassment? And let me give you a very concise argument.

626
01:05:30,440 --> 01:05:34,460
I remember one such said he worked on Oxygen 16 and I'd forgotten that.

627
01:05:34,820 --> 01:05:39,920
And I got interested in some work I was doing with John Bell on Oxygen,

628
01:05:40,400 --> 01:05:45,590
and I asked Dick a question and Dick paused for a long time and he went to the blackboard.

629
01:05:45,590 --> 01:05:50,480
He drew the entire level structure of oxygen, six team of all the spends and parrot out of his head.

630
01:05:51,170 --> 01:05:56,600
So it was a bit intimidated and we wondered why Dick, who is very obviously an Australian,

631
01:05:56,600 --> 01:06:03,770
had come to England from America at the peak of concerns about the brain drain when the US was seen as a scientific mecca,

632
01:06:04,610 --> 01:06:11,659
actually be reminded of this daily by the very large American car convertible that he brought with him from Chicago,

633
01:06:11,660 --> 01:06:20,180
which was parked outside the Department of 12 Parks Road, where we were then under pressure underneath the sign theoretical physics.

634
01:06:20,450 --> 01:06:25,960
Somebody had taken the notice note that you used to get on radiators of cars in those days.

635
01:06:25,970 --> 01:06:31,250
It said do not drain and stuck it on this notice with reference to the brain drain.

636
01:06:31,250 --> 01:06:40,549
Theoretical physics do not drain. Why did this small Australian why was he in England obviously modest man with this huge

637
01:06:40,550 --> 01:06:46,520
flamboyant car and I think it's because he was on leave from Chicago and the paradoxes removed,

638
01:06:46,520 --> 01:06:56,870
if not resolved when it was replaced by a mini a worthy successor to the Austin seven did work very hard following a burglary in the department.

639
01:06:56,870 --> 01:07:03,940
One Christmas, he used to keep next to his desk a huge electromagnetic electro mechanical calculator.

640
01:07:05,090 --> 01:07:10,520
Few people in the room old enough to remember this with a lot of buttons, and he was an absolute master at working on this thing.

641
01:07:11,150 --> 01:07:14,630
And there was a burglary in the department and the calculator disappeared.

642
01:07:14,930 --> 01:07:18,530
So the police, what was stolen? What was stolen? The calculators stolen.

643
01:07:18,740 --> 01:07:21,920
But it turned out that Dick had taken it home to work over Christmas.

644
01:07:23,000 --> 01:07:29,149
In fact, he regularly came into the department during the holidays and is known to have been in on at least one

645
01:07:29,150 --> 01:07:35,630
Christmas Day because Roger Elliott said the tells me that just after he finished his Christmas dinner.

646
01:07:36,050 --> 01:07:40,650
Dick. Hold him up, said he was in the department and would Roger come and help him evict a rather

647
01:07:40,660 --> 01:07:45,010
on a student of unsavoury habits who'd taken the living in the department.

648
01:07:45,460 --> 01:07:52,990
So some of you may remember the student Dick was a perfectionist, especially regarding things he wrote.

649
01:07:53,740 --> 01:08:00,820
What if his secretary? This was long before the advent of word processors told me that things typically went through six typed drafts

650
01:08:01,150 --> 01:08:06,820
and even then the final preprints or whatever when published would have little corrections written by hand.

651
01:08:07,240 --> 01:08:11,350
I'd like to show you an example of this. So this is the first.

652
01:08:11,350 --> 01:08:18,549
At the top is Dick's autobiographical note for Jerry Stone life and childhood.

653
01:08:18,550 --> 01:08:23,290
And on the first page, he's made three small corrections. That's what he did to his own work.

654
01:08:23,290 --> 01:08:32,770
But look what it did to the work of other people. This is your thesis from Covered in Corrections by your professor.

655
01:08:33,910 --> 01:08:43,510
By the way, one of the reasons that the memoir that NHS and I writing is taking so long is that we're intimidated by Dick's own standards.

656
01:08:43,840 --> 01:08:47,440
He wrote the memoir for the Royal Society of Durack with Rudy Pyles,

657
01:08:47,800 --> 01:08:53,590
and I remember that Dick went to the village in Switzerland where Dirac's father was born,

658
01:08:53,590 --> 01:08:57,550
to check one fact, which I don't think even made it into the paper in the end.

659
01:08:57,940 --> 01:09:03,700
So, you know, with these standards we've been it's taken us ten years to we were really kicked by the editors to get on with it.

660
01:09:04,750 --> 01:09:08,410
So I think what I learned from Dick most of all myself was professionalism.

661
01:09:09,580 --> 01:09:13,510
Get the facts tried, get the arguments right, present them clearly.

662
01:09:13,510 --> 01:09:21,969
He was the ultimate professional. He once asked me why I hadn't included something in a paper I'd written.

663
01:09:21,970 --> 01:09:27,430
He said, I know you calculated this. Why didn't you put it in the paper? And I said, I didn't think it was very amusing.

664
01:09:28,060 --> 01:09:32,080
And Dick looked at me and said, You're not paid to be amusing, you're paid to be useful.

665
01:09:32,800 --> 01:09:34,570
It's a quite a characteristic remark.

666
01:09:35,020 --> 01:09:45,040
So I think I learned a lot of physics from from Dick, but above all, I learned professionalism and I benefited tremendously, tremendously kind person.

667
01:09:45,490 --> 01:09:50,590
And from here, when I was the seven years I left till I came back to Oxford,

668
01:09:50,860 --> 01:09:56,500
he wouldn't write me long letters, corrections, suggestions about my career.

669
01:09:57,100 --> 01:10:01,030
And he wrote to me actually, rather like that remark to you, Roger, he said,

670
01:10:01,270 --> 01:10:08,079
I'm bringing this attention, your attention to a job that's come up in Oxford St Johns.

671
01:10:08,080 --> 01:10:13,840
Otherwise I wouldn't have bothered. So it's a rich college, you should think about it.

672
01:10:14,140 --> 01:10:20,080
And I took his advice. So I think we've all learned a lot and it's great to be here.

673
01:10:20,650 --> 01:10:23,799
The Dallas Institute is Dick's legacy.

674
01:10:23,800 --> 01:10:33,930
Thanks very much. Thank you for this.

675
01:10:33,930 --> 01:10:49,070
And you take issue because, of course, I was stunned by the remarks about VANIER And so was that to my statement,

676
01:10:49,230 --> 01:10:58,170
which based on the I think the idea that he was a monster is simply because

677
01:10:58,170 --> 01:11:02,280
one realised that there was something happening that we hadn't seen before.

678
01:11:02,520 --> 01:11:07,140
Of the amount of data available at the VANIER Conference was minimal.

679
01:11:07,800 --> 01:11:10,430
Yeah. Dick knew every event. Yes.

680
01:11:10,650 --> 01:11:23,920
But I mean, the the for example, I mean, in my thesis I was analysing the the world events contributed to our knowledge of the world and the.

681
01:11:27,820 --> 01:11:33,730
Back in the cities and you were talking of tends to try to.

682
01:11:34,270 --> 01:11:37,509
They weren't in the hundreds in the events. I mean, you got it.

683
01:11:37,510 --> 01:11:49,060
About the most impressive take was coming from Bristol and you know John and that car was the the man of the absolutely spent an awful.

684
01:11:49,570 --> 01:11:57,160
But when you think of the the impetus from that which led to the present development

685
01:11:57,160 --> 01:12:02,200
of technology and gender that pretty much had to do about that was immense.

686
01:12:02,560 --> 01:12:13,630
Tremendous, immense. I mean, I was with I was measuring, measuring events and I was getting five events, two eight, eight events.

687
01:12:15,450 --> 01:12:18,770
The producer. It's all you're saying.

688
01:12:19,000 --> 01:12:25,770
You think at the heart of a drug tonight that the only simplicity was you could look at you could look at a cloud chain of

689
01:12:25,770 --> 01:12:35,310
photographs and actually see a clear event and that it was strange and use that register with the with the Large Hadron Collider.

690
01:12:35,700 --> 01:12:40,740
There are so many unwanted events in your country in a different way.

691
01:12:41,670 --> 01:12:49,920
It's true. Just comes from an experiment. It's also true the the I mean, on the accelerator side,

692
01:12:49,920 --> 01:12:54,420
it's amazing those accelerators we've got working with computers that have got too much computing power

693
01:12:54,720 --> 01:12:59,610
with have too much computing power at CERN as I was on a Christmas Eve singing Christmas card nowadays.

694
01:13:00,090 --> 01:13:16,900
But they could get the space to work. Do you want to see Gerald emotionally, too?

695
01:13:22,270 --> 01:13:25,330
Yeah. That was not the only thing person.

696
01:13:25,490 --> 01:13:34,510
Everybody was jumping on bandwagons. So anyway, one of the tasks that they serve combined these experiments.

697
01:13:34,930 --> 01:13:41,110
They introduced a parameter which represented the separation of the two peaks, and they called that the duplicity.

698
01:13:44,350 --> 01:13:48,459
I think people were normalising the energy by putting the dip and the data in the same place.

699
01:13:48,460 --> 01:13:54,930
That was the story. Everybody had a statistical dip and they thought, we'll put it in the same place and get consistency.

700
01:13:54,940 --> 01:14:00,300
So of course they found a significant dip, maybe a couple.

701
01:14:00,570 --> 01:14:03,160
I would talk a few words about that.

702
01:14:03,580 --> 01:14:11,830
Still, another aspect of this work, a sort of American society, those undergraduates at the Boston University photo,

703
01:14:12,730 --> 01:14:20,860
and he left with people that just from the co-discovered countries were praying that this was coming

704
01:14:20,860 --> 01:14:29,020
quite often and that and that was an essential of those it was too long because it was great.

705
01:14:29,770 --> 01:14:37,780
And, you know, all of these people coming there were igniting interest in physics and stimulating play.

706
01:14:37,810 --> 01:14:45,400
So I think this also should be remembered that he was a very good point and he was working

707
01:14:45,400 --> 01:14:49,280
with people on hyper nuclei who were doing experiments with cosmic rays in Poland.

708
01:14:49,540 --> 01:14:53,409
You don't have to have the crack of summer school where he lectured on quarks.

709
01:14:53,410 --> 01:15:01,719
You have do have the proceedings of the of the crack of summer schools and it's could you because I'm

710
01:15:01,720 --> 01:15:06,700
trying to track down it's very hard these things probably don't exist in the UK and even when they do,

711
01:15:06,700 --> 01:15:14,680
they're done in the basement. You actually run those the crack people to my classes and I can give you the reference.

712
01:15:14,740 --> 01:15:20,290
In my fourth year and undergraduate I had this project which was basically

713
01:15:20,290 --> 01:15:26,560
directed by big science because I mean my intermediate supervisor was based in,

714
01:15:26,610 --> 01:15:34,690
in Warsaw, Poland, and I just got beneath a heartbreaking Scotland Cup, which is volcanoes in the UK.

715
01:15:35,320 --> 01:15:42,330
But the whole project was called Naked basically. You know, he had a lot of influence on the studies.

716
01:15:42,640 --> 01:15:54,170
It's quite true that. It's just something about the human side, that's all.

717
01:15:54,980 --> 01:16:02,540
And when I was writing my thesis in 64 to help on analysing this, the I think it was probably in one of the cave.

718
01:16:05,490 --> 01:16:09,690
Anyway, the decay of some of the residences coming up that he helped me with,

719
01:16:09,690 --> 01:16:15,150
some sort of matrix element analysis and getting the spin parity of what it is.

720
01:16:15,870 --> 01:16:19,050
And then but then a few years later when I was at Argonne,

721
01:16:19,800 --> 01:16:26,310
went to summer school in Hawaii and Dick was there as giving a lecture once COVID 1966 or seven.

722
01:16:27,210 --> 01:16:35,760
And at the weekend I was out there trying to do some surfing on the waves, and suddenly I found it very difficult.

723
01:16:35,760 --> 01:16:38,940
I'd never done surfing before. It sounded almost impossible.

724
01:16:38,940 --> 01:16:44,010
And then suddenly came shooting behind me. And this this big boulder, this short, stocky body.

725
01:16:45,770 --> 01:16:51,150
I was just sitting down on the board. And so a certified industry.

726
01:16:52,310 --> 01:16:57,930
And that's that's true. That's true.

727
01:16:59,790 --> 01:17:08,219
Most of us who came after that. Then you remember him on his bike and sitting in that second row there with a black book.

728
01:17:08,220 --> 01:17:12,510
He used to take notes and he came to every seminar and felt it's kind of not quite right.

729
01:17:12,630 --> 01:17:22,530
And as you say, he really actually made a comment, but it was clear that he beat and in fact, if the film was too speculative, that,

730
01:17:23,520 --> 01:17:32,570
you know, he'd have a few of those printed people in those days, especially a couple of spectators or something on the bandwagon.

731
01:17:32,580 --> 01:17:36,780
Such creativity is not. We.

732
01:17:37,060 --> 01:17:42,570
You do it as much as we should not. But certainly those of us that does politics do remember that.

733
01:17:42,960 --> 01:17:48,380
And maybe something has rubbed off. Well, I mean, let me just comment on that.

734
01:17:48,390 --> 01:17:53,610
I think I mean, in a sense, it's a paradox that Dick, you know, it was not a speculative person.

735
01:17:53,610 --> 01:17:58,980
It was regarded as not a speculative person who didn't speculate much in public about party violation.

736
01:17:59,250 --> 01:18:04,650
And yet he pushed the court model, which the rest of the world regarded as totally ridiculous and speculative.

737
01:18:04,830 --> 01:18:08,580
And the reason was it understood interpreted the data.

738
01:18:09,060 --> 01:18:21,180
That's because by 1934, his work on the Saul Goodwin ancestry was in a package that he put on the back of his mind.

739
01:18:23,930 --> 01:18:32,190
So God told me that if there was a knock on the door that a black man that

740
01:18:32,190 --> 01:18:36,380
told him off very seriously that he should look at these things much better.

741
01:18:36,410 --> 01:18:47,370
And he just said it was so right. Nice words on which to end this seminar.

742
01:18:47,490 --> 01:18:54,150
And I think we have really been pretty fortunate to have two such excellent talks by the students.

743
01:18:54,360 --> 01:19:00,780
Not just the physics, but also the human dimension, which is, after all, what lends value to what we do.

744
01:19:01,380 --> 01:19:05,220
And so let's first hand Frank and Chris for the talks.