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Credit: Mary Samios
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Interview of Nicholas Samios by David Zierler on July 1, 2020,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
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In this interview, David Zierler, Oral Historian for AIP, interviews Nicholas Samios, Director Emeritus of Brookhaven National Laboratory. He describes his family’s Greek heritage and he recounts his childhood in Manhattan and the value of the education he received at Stuyvesant High School. He describes his decision to attend Columbia as an undergraduate, where he studied under Jack Steinberger, Polycarp Kusch, and I.I. Rabi. Samios explains his decision to remain at Columbia for graduate school, and he explains some of the exciting things that were happening in particle physics then, including the use of cloud chambers to discover the “strange particles” called lambdas and thetas. He describes his dissertation research studying these particles using bubble chambers and searching for parity violation, and he explains his interest in the research at the Nevis Cyclotron in Westchester. Samios discusses his postdoctoral research at Columbia before accepting a position at Brookhaven, which was in the middle of building the Alternating Gradient Synchrotron, and he describes the difference between this work on pions and what Panofsky was doing with electrons at Stanford. He describes his subsequent work designing neutrino beams and his contribution to the discovery of the baryon charm, and he describes his tenure as chair of Brookhaven’s physics department and his efforts to produce complementary and not redundant work with the other National Labs. Samios recounts his time as Director at Brookhaven, and he describes in detail the ISABELLE project and why it was cancelled by the Reagan administration. He connects the fall of ISABELLE with the origins and ultimate failure of the SSC and the inevitable loss of leadership the U.S. experienced in high energy physics. Samios discusses why the RHIC endeavor delayed his retirement and the significance of RHIC’s discovery of the quark-gluon plasma. At the end of the interview, Samios surveys the fundamental discoveries that occurred over his career on the Standard Model and parity conservation, the ongoing mystery of dark matter, and he outlines the many ways that particle physics has positively influenced technology and human well-being.
This is David Zierler, oral historian for the American Institute of Physics. It is July 1st, 2020. It is my great pleasure to be here with Dr. Nicholas Samios. Nick, thank you so much for being with me today.
Fine. It’s a pleasure.
OK. So, to start, would you please tell me your title and most recent institutional affiliation?
My present title is Director Emeritus, Brookhaven National Laboratory. And my last association was with Brookhaven National Laboratory.
OK. And now, let’s take it all the way back to the beginning. Nick, let’s start with your parents. Tell me about them. Where are your parents from?
My parents were both immigrants from Greece, from an island called Kythera, which is off the southern coast of Peloponnesus. And they both came to the US separately, my father as a young boy, maybe 16, 17, 18…[he] came to the US from Kythera via Athens, and came to New York and became a restauranteur. If you want details of that, I’ll tell you in a minute. My mother came—her mother died in childbirth. My mother was maybe 4, 5, and her father came to the United States in the Cambridge area, Cambridge, Maryland, and left the daughters in Kythera with a relative. And, after a few years, sent for them and they came to the US to Cambridge, Maryland. And my father started work as a—said he walked up from The Battery until he found a restaurant, and he became a dishwasher, and then a salad man, then an oyster man. And then, after a certain number of years, he opened a restaurant with his partner, the Rockaway restaurant on 42nd Street, and that was his life. How’s that?
[laugh] That’s great. Did you grow up helping in the restaurant?
Not at all. It was a seafood restaurant, rather large, two floors. And it opened for lunch and dinner and then it closed late at night. It had a great seafood selection. And he sold it after the Second World War, about 1948 or ‘49. And by that—I was only 7, 8 years old. I used to have lunches at the restaurant and dinners. And between schools I used to stop by for a spumoni or tortoni, but I never had the opportunity to really work in the restaurant. It had a very long bar. It was a very well-known establishment.
What neighborhood did you grow up in, Nick?
I grew up in Manhattan. The restaurant was 42nd. I lived on 40th, between 2nd and 3rd, a very polyglot neighborhood of a whole bunch, Italians, Greeks, Germans, Irish, Jewish, you name it.
You grew up in a townhouse or a high rise?
In an apartment house, five story apartment house rental. I was on the second floor. You walked upstairs. In those days, all apartments were about five stories high because, if it were higher, you needed an elevator.
And so everyone built an apartment house five stories. And it was a pleasure. Lots of kids on the street. Learned to play stickball very well and went to the public schools.
Was Greek or English your first language?
Mine was English. My wife’s was Greek, so it varied. But mine was English. I learned Greek because, in addition to going to the regular public school, there was an afternoon Greek school from 4:00 to 6:00. So, for five, six years I went to Greek school in the afternoon, so I learned Greek.
Was education important to your parents for you?
I think so. They wanted me to be somewhat familiar with the language, and it did work out. It was useful, also. The language was useful for later years. Many words, all sorts of things have Greek derivatives. But it was also camaraderie. It was worthwhile.
What was your family’s religious observance when you were growing up?
They were Greek Orthodox.
And so what kind of holidays would that mean?
Well, my mother was religious. She’d go to church every Sunday. My father was running the restaurant and he had every other Sunday off, but he would go occasionally. But the family always went to Easter, especially Easter Week was a very special time. That was a major holiday, and other saints’ days, but mainly Easter. In fact, one of my fond memories was, on Easter, the Resurrection Service goes on from midnight to 2 o’clock in the morning. And so my father was a trustee at the church, at the cathedral on 74th, and so he’d have the restaurant set up for us and friends. And about 2, 3 o’clock in the morning, we’d go to the restaurant and have a meal, which is the Easter meal. And we’d eat ‘til 4:00, 5:00 in the morning and we’d go to our apartment. And, on the way, I remember seeing Catholic priests going to their church nearby, so it was a fond memory.
Nick, did you go to public school all the way through 12th grade?
Yes. I went to—could even tell you them—PS 116 on 32nd Street. So, I used to walk from 40th to 32nd, even when I was first, second, third grade, a group of us. And then I went to Junior High School 40, which was on 20th Street. That was from 7th to 9th grade. And then I went to Stuyvesant High School for high school.
Oh, you went to Stuyvesant?
Yeah, 15th Street on the east side. Public school was a great education.
Now, you going to Stuyvesant, did that mean that during your middle school years you were particularly strong in math and science?
I was strong all around by junior high and public school. But, no, there was no strong science. I was a good student. But then, when I got to Stuyvesant, it was very good in math and science, but it was also very good in social studies, and the English department had distinguished people there, in economics. It was a well-rounded high school.
Nick, did you know at Stuyvesant that you wanted to focus on math and science, or that only came later at college?
I was strong in math and science, but I didn’t take that—the numbers side, the chemistries and physics, that was it. The math was very strong, all the algebras and geometry, so a very strong math department. I really didn’t make up my mind until early college.
Where did you apply to school? Did you want to stay in New York, or you applied beyond New York?
I had to stay in New York because my father was not in great health, and so I might’ve preferred going out, but I applied to Columbia and I got in, and that worked out just fine.
Columbia is a pretty good place to be, with it being so close and being such a wonderful university.
And it was especially strong in science and math at that time. I could name all the Nobel laureates that were at Columbia, all were going to become Nobel laureates, so it was very, very strong. In math, too. I remember, although I was interested in science, I didn’t know what science, so Columbia set up a special math sequence for people who were interested in sciences. And a man by the name of Samuel Eilenberg, a very distinguished mathematician, member of the national academy, taught this elementary course to a bunch of eager young kids. And there was a large nucleus who were interested in science who joined that class. So the instruction there was great. But, as you know, at Columbia, the first two years, you’re not specializing, you’re taking the core curricula, which is in the humanities and contemporary civilization, which is fantastic. So everyone is taking the same courses for the first two years with some electives. So math and some physics were electives, and that was my road to science after that.
And how did you know you wanted to focus on physics? When did you make that decision?
I think it was the second half of my first year. I never liked chemistry. I found that just complicated and so I wanted something more interesting, and physics really struck me as—and there was a whole group of us that sort of meshed in [Samuel] Eilenberg’s class. And we all went in physics, maybe 10, 15 of us became physics majors at that time.
[laugh] Nick, who were some of the professors in the physics program that you became close with?
Well, the first one was Jack Steinberger, who became my thesis advisor way down the road. Then, the other people I had courses with was Polycarp Kusch, who became a Nobel laureate. James Rainwater, I took a nuclear course with him, became a Nobel laureate. I took a course with Rabi who was a Nobel laureate. And they were all around, and people would come from around—Gell-Mann would come to give a course, so we met really high-powered guys. It was really glorious.
What was it like to take courses from Rabi as an undergraduate?
Well, I actually took courses with Rabi as a graduate—Rabi privately was a brilliant man and a great man. I got to know him very well later on. But privately he was a terrible teacher. [laugh] He was a great guy, but he gave a course in I think statistical mechanics—no. I forgot. I think it was statistical mechanics. It was the same course over and over again, and it was not very informative. But it was great watching him think and talk off the cuff. But he was a great man. I could tell you many stories about him.
What was Jack Steinberger working on during your days as an undergraduate?
He was at Nevis. He was in particle physics. He was doing experiments with pions and muons at Nevis. I didn’t know him as an undergraduate. I knew about him when I was a senior.
Oh, I see. Did you have any internships or summer jobs that were related to physics as an undergraduate?
Yes, yes, yes, yes. Not as an undergraduate, no. The way it played at Columbia was, when you became—going to go into physics after you graduated the college, you became a teaching assistant. And so that paid for your tuition for your graduate courses. And, after you finished your courses for two years, you became a research assistant whereby you did part time helping other physicists, which paid for your time as doing your research. So you had some money coming in as you went from the first two years of graduate school to the second two.
How did you know—
So one of the teaching.
Nick, how did you know that you wanted to stay at Columbia for your graduate program?
Because you were able to really get started by your senior year as an undergraduate.
You could take graduate courses, and so you really got a head start. And the faculty was just very, very good. It was terrific.
So you didn’t really give much thought to going somewhere else?
No, I didn’t, I didn’t. And many of us didn’t. There was a whole group of us. I’ll mention Mel Schwartz, who was a colleague. He went to Bronx Science and we were students together, and we went into graduate school together. And we both had Steinberger as a thesis advisor and then so on, we interacted throughout our careers. But there are many people like that, that just went from the college into graduate school, maybe 10 of us. I forgot. Some large number.
Nick, I’m curious; with your parents as immigrants and you living a working-class life growing up, when and how did it occur to you that you had what it took to pursue physics at a high level? When did you come to that realization?
It was hard. What I fortunately was able to do—I was always very good at school, all courses, and so I was just thinking, what do I really want to do? And, as I said early, as we noted earlier, math was a strength, and science was a strength. But, as I said, I never took biology and chemistry. I took chemistry high school courses, but I never really took biology, and I just was interested in physics. And you’re good at it, and the other thing was there’s a camaraderie at Columbia, and we all were together interacting, and it was fun. And it turned out luckily Columbia was a great place to be. I know you could’ve been at Harvard, you could’ve been at Princeton, equally good, Caltech, equally good. But I had reservations. I had a father who was not well, and, in fact, I graduated college in ‘53, and I got my Ph.D. in ‘57, and my father died in ‘54. So, I had to be around. So, it really worked out well.
When you were thinking about graduate school and graduate work, were you already pretty committed to particle physics and doing experiments, or were you still open to other ideas?
No. I was not committed until late in my—what happened is I graduated and the first two years you’re just taking courses in graduate school. And it was during that time it became clear that particle physics was the thing to do. We had Serber at Columbia teaching, who was a great man in the field. And Jack and Leon Lederman were there, and Vernon Hughes. There were a whole bunch of people in particle physics. And so, what happened is that, when we went for our thesis professor, three of us got together, Mel Schwartz, Myself, and Jack Leitner, and we all joined Steinberger as a thesis prof. He took us all on, which was terrific. And we had a very exciting 10 years together or something like that.
And, Nick, what year was this when you started graduate school? This would’ve been, what, 1954, ‘55?
Yeah, ‘53, ‘54.
What were some of the most exciting things going on in particle physics during that time?
Well, an exciting thing in particle physics was the new particles were being discovered. It was just the time when—there were neutrons, protons, electrons, but cloud chambers started saying there were other particles, called them strange particles, lambdas and thetas at that time. And so, people were trying to say there’s something new here, and people were looking for more of these particles. How were they produced? What were their properties? And so two things happened: One, Murray Gell-Mann came up with the concept of strangeness to explain the peculiarities of these particles. For instance, the lambda was produced strongly in interactions, that means in times 10 to the -23 seconds, but when it decayed, it decayed at the same particles in 10 to the -10 seconds. So how come it was so slow? And so Murray said, “It’s strange. They have something strange about them.” So, one was interested in producing these things. And the second thing was the Glaser invented the bubble chamber, a new device. And, in fact, what had happened, I had joined Steinberger first and I was in the process of building counters. I had built some scintillation counters ready to do an experiment on pi-nucleon interactions. And Jack had gone to a conference in Glasgow where the Gell-Mann scheme came out, and the bubble chamber was out, and he said, “Drop everything. We’re going to build a bubble chamber. We’re going to look at strange particles.” And so we did that, the three of us with Jack; Jack Leitner, Jack Steinberger, Mel Schwartz, and myself. And we produced a great deal of physics over the next years, producing these strange particles at Brookhaven and building several bubble chambers to exploit this new field of physics.
Can you explain, Nick, what bubble chambers did that spark chambers weren’t able to do?
No. Bubble chambers came before spark chambers.
Oh, I’m sorry. Right. I meant the other way, right.
Yeah. It was cloud chambers, and cloud chambers were not a great density. Bubble chambers were liquid so their densities were an order of magnitude higher so you could get more interactions and you could cycle them better and you could make them bigger and they were more controllable, and they had a very high resolution. So they were a technique that, when it was invented in the early ‘50s, it went on to—I would say 30 years they got bigger from a few—10, 20 liters to 10,000 liters of liquid. And so that became a very powerful technique which I exploited for many years.
Can you explain, Nick, how you put your dissertation topic together? Did Jack give you a problem to work on, or you came up with something mostly on your own?
Well, no. People were trying to study these strange particles, and one thing that came up was an experiment in the cloud chamber by Shutt et. al. that showed these strange particles were produced in association. He made a lambda, he made another strange particle, lambda-theta. So, when we built our bubble chamber, we said let’s—with the bubble chamber—they did it in a cloud chamber. They could get 20 events; we could get hundreds of events. So we built the chamber and exploited it, and what happened is the three of us worked together on building the chamber, the optics, running the experiment, analyzing the film together. And then, when we, Mel, Jack Leitner, and I got theses on this run, and Mel took one topic, Leitner took another, and I took a third. So, in other words, we all worked together with Jack Steinberger to go into this new field starting from scratch, building the chambers, scanning the equipment, doing the exposures at Brookhaven, the Cosmotron. But then, the film had many, many things to look at, and each of us took a topic. And Jack Leitner took the pi-P scattering, Mel Schwartz took associated production with sigmas, and I took associated production with lambdas, and we each got a thesis on that.
What were your principal conclusions in your thesis?
[laugh] Well, it was just verifying that they were produced in association, and I looked hard for parity violation. T.D. Lee and C.N. Yang had come up with the idea that in weak interaction, parity was violated. But one way of looking at it was to look at lambda decays and looking at the decay distributions. Well, I did that, looked for it, and I had a two standard deviation effect of the lambda parity being violated, but it was not great enough. About a year and a half later, when we had a bigger chamber and more events, when we had 300 events, we were able to demonstrate parity non-violation. But, if I had a bigger chamber with more events, I would’ve discovered parity violation, but I didn’t. But that was fine. It was an excitement. But then I just looked at the angular distributions on how they produced and decayed.
How did this work in your collaboration with Jack and your other students; how did it contribute overall to some of the really exciting and major developments that were happening in particle physics in the late ‘50s and early ‘60s?
Well, we were in the midst of it. What happened was, after I got my degree at Columbia, I stayed for two years an instructor, and there was an interim where the Cosmotron machine at Brookhaven had some difficulty and had to be shut down for a year or two. And so, during that time, I transferred my attention to experiments at the Nevis Cyclotron at Columbia in Westchester County. And then, we did several experiments and, in particular, what I focused on was to measure the parity of the pi zero meson, and this involved looking at the bi-0 decay into electrons, four electrons in particular, and measuring their distribution. And I took roughly 100,000 pictures and I got 200 events. And I led the group on that, and we showed that the parity was negative. The charge pions were known to be negative parity, and I was able to demonstrate in this tour de force that the neutral partner was also negative. But we also did an experiment looking at pi-e decay, which was very relevant at that time, to look at the nature of the weak interaction, whether it was vector, axial vector, pseudo-scalar, blah, blah, blah. And we, by looking at the pi-e decay, which was very rare, were able to show that the interaction was V minus A, vector and axial vector, which was also a nice thing. But, when I left Columbia and went to Brookhaven to the physics department, Sam Goudsmit, who was the chairman of the department at the time, hired me.
But, Nick, this was not directly after you defended? You were at Columbia as a postdoc for a few years, right?
That’s right, that’s right. What happened was I got my—yeah, I got my degree in ‘57, and then from ‘57 to ‘59 I was an instructor at Columbia. And then I started teaching in ‘56, in fact. And then, in ‘59 I left Columbia and then I went to Brookhaven as a physicist, and then joined a large group. Shutt, the guy who built the original cloud chambers and observed associate production, and he was in the process of building bigger bubble chambers, and I thought that was a great time to go and exploit this field, and it turned out to be right. So, what I did was, at that time, Brookhaven was building an accelerator called the AGS, Alternating Gradient Synchrotron, which was a big step up in energy from all other accelerators. Accelerators at that time were 1 GeV or 3 GeV, and Berkeley was 6. This was going to be 30. And so I went there, and I was able to exploit that machine for several years. And, in that time, using—I don’t know how much detail you want, but you could make beams of strange particles, K minuses, which then you used to interact with hydrogen and to look for more strange particles. And, over the years, we discovered several important ones, such as the phi meson and the cascade star baryon, which then, with other things that were going on, led Murray Gell-Mann to the SU(3) symmetry scheme, which categorized all these myriad of particles into families. And he had a prediction, if this was true, on a particle called the omega minus, which was—if this scheme was correct, this particle should exist. And we then led the team that searched for it and found it in 1964.
Nick, how did you make the decision to go to Brookhaven fulltime?
Well, several reasons. One, it was really the hot place to be because the AGS machine was being built, and it was going to be the next big accelerator.
Nick, what were some of the big goals with this machine? What was it looking to accomplish?
Oh, that’s very funny, because the proposal for this was written by the director at the time, Leland Haworth, and it was a three-page note to the AEC at the time. And he essentially said, pions are interacting and cyclotrons are pretty good, but it would be more interesting to go to higher energies. And you say, that’s all he said? He said going up in energy is going to be very, very interesting because of the interaction between pions and nucleons. But then, the reason the AGS was so nice, it had a cute new idea of how to build accelerators called the strong-focusing scheme. It was Courant, Livingston, and Snyder who found that at Brookhaven. And you were able to build a machine much cheaper, much smaller to get to those energies. And so this whole new machine was coming out, so opportunities for doing this physics that I was interested were right there. The other place to have gone would’ve been Berkeley. That was the real center. Also, Lawrence had built a great laboratory there, but it was soon to be eclipsed by the AGS.
Were you following what Pief Panofsky was doing at SLAC right around the same time?
In the ‘60s, Panofsky was out to build an electron accelerator. That was a different thing. Their great strength was in building cavities that can accelerate electrons very nicely. So Pief’s source was a different scheme. He was interested in electron interactions. I was interested in proton interactions to produce pions.
So they did beautiful experiments at SLAC, as you know, with a great machine. And I think, in the history, the SLAC machine that Panofsky built and the AGS at Brookhaven were two of the most productive machines in producing physics over the years that we know of.
Nick, I’m curious; you really came of age professionally right in the middle of Sputnik. Of course, it was a different field than the one you were interested in.
But I wonder, looking back, if you can tell what kind of impact that Sputnik had on the physics community generally and the kinds of opportunities that it may have afforded you personally?
It had an enormous effect. What happened was, going back, Eisenhower was president of Columbia University for a while before he became President of the United States. And, while he was there, Rabi had a great influence on him. So, when Eisenhower became president, he set up the Presidential Science Advisory Committee to the President, and he had essentially offered Rabi the chairmanship. He decided not to take it and he said it should be Killian, and so that was set up. And so, when Sputnik occurred, if you look at the budgets for science, they increased enormously. And, in fact, one reason I was able to go to Brookhaven is because its science budget increased a great deal to be able to do all this science. So Sputnik spurred a huge investment in science, and that had a direct effect on my whole generation of physicists because opportunities were numerous.
Did you see your work at all as contributing to the national defense? In other words, all of the funding for Sputnik was about not letting the Soviets get ahead.
Yeah, yeah, yeah, yeah. No, but—I’ll give you a story. Bob Wilson, who built Fermilab, was at congressional hearings and they asked him, what benefit is your accelerator going to do mankind, and things like that. And Wilson said, “Nothing.” He says, “But it adds to our knowledge to training our people in understanding and doing science. But it adds to our humanity and our seeding of knowledge.” But the way I would put the Sputnik thing was it really trained a whole generation of scientists, who then really benefitted all sorts of things. You look at the electronics industry, the transistor and stuff like that, that’s Bell Labs science, which was pure science. And you don’t know where the next breakthroughs occur. You do good science and good things come out of it. That’s the way I would like to put it. But the attitude towards science and Eisenhower’s promotion of it, the science committee and Killian and Rabi, and some funding good science—Panofsky got this thing built, what, in ‘62, ‘63?
And so it spurred—just blossomed science.
What was the first project you worked on at Brookhaven? What group were you part of?
I was part of the Shutt group. It was a large group, and I helped design beam lines for the AGS. In particular, there was what was a called a “separated beam,” which you collided a proton with a target and you picked off particles that were produced, such as K minuses and antiprotons. And then you used them to interact in hydrogen to study in detail their interaction properties. Produced lots of stuff and you studied.
And when you say, “large group,” what does that mean? How big?
And what was the hierarchy there? Who would you report to and who would report to you?
Yeah. Oh, the way it worked was there was a group leader, and the ranks were assistant scientists, associate scientists, and scientists, and below that postdocs. So that was the ranking. And then, above the group leader, there was a chairman of the department, and above that a director, like Haworth. And so it was a hierarchy.
And how long were you with that original group?
I was with that group for probably 10 years.
And what were some of the key contributions that that group had made during that decade?
Oh, they discovered the anti-cascades. As I said, we discovered the phi, many resonances, mainly contributing to particle physics. The resonances, their spin parities, their properties, antiparticles. And Shutt did a great thing. He made his chambers that he built available to university groups. The fact that each experiment used film, you could do a certain energy, pion interactions or proton interactions. And the university group would take the film, go to the university, analyze the film, and publish it independent of Shutt and the group.
Nick, I’m curious how well connected you felt to the academic community working in a national lab? In other words, would there be people that would come from places like MIT and Berkeley and Princeton? Would they visit Brookhaven? Would you interact with them? And, conversely, would you go to academic departments and share the findings of the group that you were working with at the time?
I would say it was very strong interaction at Brookhaven. Brookhaven contracted with Associated Universities, Inc. They got the contract from the AEC, then DOE, and that corporation, AUI, was composed of nine universities on the east coast. I’ll give you some of them: MIT, Harvard, Columbia, Yale, Johns Hopkins, Pennsylvania, Cornell. Princeton and Rochester. All those universities had two trustees on the board, and they selected the director, and they had oversight over the thing. And Brookhaven was built for users, so whenever the machines were built, like the cosmotron or the AGS, its history, 80% of the time, the number of users, the time on the machines, was allotted to outside universities. The way you got on is you made a proposal, there was an advisory committee to the director or the appropriate director that said, yes, no. And universities were successful at getting 80% of the time on these machines. So, Brookhaven was noted as a friendly user laboratory. And there was an interchange between people from Brookhaven and universities going back and forth periodically. And so it was a very close attachment between these and other universities and Brookhaven. So it was known as an academically-oriented establishment.
Nick, what was your next position after those initial 10 years with your first group?
Well, I was in the Shutt group and, at a certain point, another group, its group leader retired, he was E.O. Salant and he retired to Vanderbilt. And I was given charge of that smaller group, so I ran that group for a number of years. And then I became chairman of the physics department for five years.
Now, when you replaced Salant in that group, the second group, what were some of the research objectives that were going on then?
They were very similar to what was going on before, but we did a small change. We started to do neutrino physics. In the early ‘60s, Mel Schwartz invented this scheme that says, oh, you want to understand weak interactions, so why not make a beam of neutrinos? Otherwise, neutrinos were observed by the beta decay of nuclei. You take a nucleus, cobalt 60, it decays into an electron, another nucleus, and a neutrino, but they are very-low energy neutrinos. But you want to look at the interactions of high-energy neutrinos. So, I got into the business with helping design neutrino beams at Brookhaven and doing experiments with high-energy neutrinos because that probes the weak interaction at higher energy, so you scatter neutrinos off nuclei and study what comes off. And so I got into that business with the new group. And we did several things studying, as I’ve said, the interaction of neutrinos with nuclei, axial-vector form factors. And also, luckily, during this time, we were able to do some spectroscopy and we discovered baryon charm. In a sense, a new—well, there were the quarks. Let me go back a bit. We know now that protons and neutrons are not individual, they’re composed of three quarks and gluons. And the quarks were up and down. And then, with the lambda will have a strange quark, there were three quarks. And people said, oh, there are more. And, yes, there was a fourth quark that came up, the charm quark, which was the J/psi particle discovered at Brookhaven and Stanford. And that was a boson, that means nucleon number 0. Then the question, were there baryon charm? And so there was an idea by Glashow that, by interacting neutrinos on protons, you might produce charm particles. And we did that, and we discovered the first two charm baryons, for instance, called a sigma sub-C and the lambda sub-C. So, we got into the business of looking at neutrino interactions.
Did you directly work with Shelly or you were just aware of some of the theories he was putting forward?
Work with who?
With Shelly, with Shelly Glashow?
No. Well, Shelly was just a great friend. There are many phenomenological theorists, and he was one of the good ones. And we always interacted in the early games of strange particles and so on. So, when he went to Harvard, we were in communication all the time. And so this was a cute idea. We solved some problems and so we did it, but we were always talking to—Shelly would come up with an idea, what about this, what about that particle? Is it spin that really correct—and so on. So, as an experimentalist, we always talked to the theorists who did calculations, you know, interact with the experiment. And Shelly was one of the more prominent ones.
And then, Nick, you said you became chair of the physics department.
What did that mean, in terms of were you setting policy? Were you setting the agenda for the kinds of projects that were going to go on at Brookhaven?
Yeah. The physics department had several hundred people, about three, four, five groups, theory and experiment. And you essentially were the chief operating officer of that. You monitored the physics, you were responsible for the funding, and you made decisions on personnel and what barriers you’re going to exploit and so on. So that was OK. Thank God things were great. I was able to spend half time doing physics while being chair.
So that worked out very well.
Nick, I’m curious; from the vantagepoint of being chair of the physics department, did you feel like it was important to know what was going on at the other national laboratories so that—
—everyone could avoid doing redundant work? Was that something that you needed to stay on top of?
You always interacted with your fellow laboratory guys. You competed, but you certainly didn’t want to do anything that—just doing something that someone else has done. You wanted to do something better, or if you think it was done badly or incorrect, you can do that. But you want to make sure you’re exploiting the interesting physics. And the other thing is, you really want to pay attention to the personnel, hiring bright young people and taking care of them. My idea of a good administrator was like Haworth. They should not be aware of the budget situation; they should just be concentrating—your young people should all be concentrating on doing the science and not the politics or the money or anything else. That should be left to the chair or to the director, depending on the level of stuff.
So, Nick, in terms of identifying the best physics that should be done at Brookhaven, what are some examples of things that you felt that Brookhaven did better than anyone else, and what are some examples of areas of physics where you were happy to say, you know, that’s not our strong point; I’m happy for another lab to take the lead on a given topic?
That’s a very interesting question. You’re probing my mind heavily now. That’s great. For instance, I’ll give you an example where I pushed to get out of areas. For instance, nuclear physics—well, it was a great time to study all nuclei, Van de Graaffs, low-energy nuclear physics. But, after a while, it became dull. You found another state, it didn’t make any difference. But some people always liked to do what they’ve done as a graduate student the rest of their life. And, slowly, you got to get that changed and get into the modern age. So, some areas of nuclear physics I saw were not as good as they should be. And so you slowly closed it out. And so you also tried to get into newer areas of physics. Like I said, neutrino physics, you see that’s an opening that we went into. And the other thing is, the aims of particle physics was always going to the higher energies as much as you can. And so you invest in accelerator physics. You tried to come up with new ideas and strong focusing was one of the great ones at Brookhaven.
What made it great?
It made the cost of building a machine at a given energy an order of magnitude cheaper, and you could make them bigger. After a while, when you’re doing cyclotrons, you just can’t scale them up. The amount of iron is just so enormous it becomes unfeasible. So, you need a new clever idea, and so all the machines since then, the AGS, the SPS, the Fermilab machine, all are built on the strong-focusing principle. And the LHC at CERN, and so on.
What do you see as your key achievements as director of physics at Brookhaven?
As director of Brookhaven?
Well, I don’t know if you know about ISABELLE.
I do. Please, talk about ISABELLE.
OK. ISABELLE was a project which was conceived correctly, originally a 200 GeV PP machine. And one started doing design and stuff like that, and one of the key questions was the magnet design. It had to be superconducting. And then the community said, my God, you shouldn’t do 200, you should go to 400. And so, the design of the magnet that Brookhaven chose at the time was what is called a “braid magnet,” and it would’ve worked at 200 GeV energy. But, when the thing came to be 400, double the energy, the circumference was increased a bit. but the magnet-required field was increased more. And that demand of the higher magnetic field, the braid design just wasn’t up to it. And so, there were difficulties in making it work. And, at that point, I was asked to get involved in that. I was doing physics, and because of the difficulties, there was a change in management, and I became director. And I changed the design into what is called a Rutherford cable design, which had been proven to be working well. And we fixed the magnet problems in about a year, but it was too late, and the project was canceled. So, ISABELLE was canceled in ‘83. I became director in ‘82. And so there was an issue; the future of the lab was at stake.
And why was it canceled, Nick? What do you think happened?
Say that again.
What happened with ISABELLE, why was it canceled?
Oh, it was canceled for a variety of reasons. One, the Reagan administration came in and Keyworth became a science advisor. And, when anybody new comes in, he wants to do something new—and this is a private opinion—he was looking around, how could he do something new. And there were other people in the high energy community who wanted to build a much bigger machine called the desertron or anything else. And Keyworth didn’t have the money for that also, but, if he killed ISABELLE, he had some money. And he promised the community that they would get this big machine. And so, there were many committees to review ISABELLE. And I called it CBA, because I changed the design. And some of the committees said, yes, you should go ahead, get this solved now, but you need to have the money to do that and keep other things going. And so, under stringent budget things, they said, no, we’ll kill it and we’ll go for the big machine. And so it got killed, and that’s when the SSC concept came about. And I don’t have to tell you that story, because the SSC took a while to get going. And there was a design, and it got killed in ‘93.
You remember that, right?
And what happened, in a certain sense, the logical thing would’ve been to finish CBA and then build a site filler at Fermilab. But people were promised a golden goose and they believed—in fact, when they killed CBA/ISABELLE, I appeared before the HEPAP committee and I told them Aesop’s fable about the dog with the bone in his mouth and came to the edge of a lake and looked in the water and saw a bigger bone, and went to get it and lost the bone he had in his mouth. And that’s what happened. SSC had a design and then the style of doing big machines changed and a more NASA type of thing had got out of the hands of scientists, and the cost just skyrocketed from 4 billion to 8 billion to 12 billion. And it was bad—they got a site in Waxahachie, Texas, and they spent a couple hundred million dollars—no, a billion dollars, and then it got closed down. And that was really the demise of high-energy physics in the US. But there were many, many people who contributed to its demise. There’s a book called Tunnel Visions that describes the whole thing.
Right. It’s the whole autopsy, right? [laugh]
[laugh] Well, not everyone was behind the SSC.
We supported it, by the way.
Yeah. Nick, I wanted to ask about that, because the design phase—from ‘89 to ‘93, this, of course, is smack dab in the middle of your tenure as director of BNL.
So, I’m curious, from your perspective, what did you see as the impact—during the early years when it seemed like SSC was really going to happen, what did you see as the impact that this would have on Brookhaven? Did you see this negatively? Was it a threat to Brookhaven—
—or would it be sort of—
It would not be a threat?
No. I would say, look, that decision was made. You don’t go back on it and you say, look, we’ll support it, and we’re not going to be in the particle physics game. We’re going to be in the relativistic high-energy heavy-ion game. In fact, the new concept came in to look for the quark-gluon plasma. The concept was, if you use heavy nuclei—one, in high-energy physics, you deposit lots of, lots of energy into smaller and smaller volume looking for new things.
And heavy ion, you deposit a large amount of energy into a bigger and bigger nucleus to heat it all up and see new things. And the concept of RHIC, the heavy-ion machine which we ultimately built, was by heating it up very high, all these protons and nucleons all dissolve and you have a sea of quarks and antiquarks, gluons for 10 to the -23 seconds, and then they freeze out and you produce something new. So, the question, do you see this new form of matter? So, there was a great excitement in what I would call the particle nuclear community to look at really relativistic heavy ions. And so, I said, well, we’re going to go into a new field. And, on top of that, we’ll be doing polarized protons and so on. In fact, in the end of the ISABELLE/CBA thing, when I tried to salvage CBA, I said, not only could we do proton-protons, but, because we had a tandem machine, a nuclear capability, we’ll be able to do nuclei in this machine, and also polarized protons.
So, as a second-tier thing—I originally already had the idea of using heavy ions. But, when ISABELLE got killed, I said, forget that; let’s now concentrate on the nuclear part. And the nuclear community supported it. We went to many workshops and meetings and events that supported it. So, then we said, OK, we’re going to go and build the highest-energy heavy-ion machine at Brookhaven. On the other hand, SSC was being built, and we said, we’ll support it. People wanted to go do physics at the SSC, we’ll let them go. And, in addition, we were one of the two labs which developed superconducting magnets for the SSC, we and Fermilab, and each of us collaborated with an industrial partner. We did with Westinghouse, and Fermilab did with some other company, I forgot which. And so we successfully built many, many magnets for the SSC prototypes, so that industry could only do it. So we were strong supporters of SSC, but not all people in physics were supporters of the SSC. The community was not completely united, and there were difficulties in the management. Everyone thought they were managing it. And then there was Congressman Mr. [John] Dingell and other people who didn’t want science or something, and it was a mess.
You said that when the SSC was killed, that it was essentially the end for high-energy physics in the United States. What do you mean by that?
Well, the torch went to CERN. They built the LHC and the Higgs was discovered at CERN, right?
Right. But what does that say about the ongoing relevance of places like Brookhaven and Livermore and Fermilab? In what ways were they not able to pick up the torch where SSC failed to light it, so to speak?
Well, we’re trying to do that now at Fermilab. Fermilab is the lead lab in high energy. And there’s a big neutrino program going on there. I mean, they’re really focusing on neutrinos. There’s the DUNE experiment, and so the high-energy frontier now is not in the United States. So, one can go and do other high-energy physics with higher intensity, what we call the intensity frontier, and to try to do great physics there. But, on the other hand, if you look at CERN’s LHC, the energy that—they also didn’t help with the SSC because, essentially, they said, well, if you turn it off, we’ll do the physics. But their physics is—SSC was 20 on 20, 40 TeV. The LHC is, I don’t know, 5 on 5. It’s—I forgot the energy, 10 or 11, quite a bit lower than the SSC. So, the main thing they found is the Higgs but nothing else really so far. And maybe the answer is the energy is too low, and the SSC—but now you can’t go to the SSC. What’s the next machine you build after the LHC? It’s going to be enormous, and it’s going to be enormous cost. So it’s a slow time now in particle physics. Maybe the Chinese will build it. Maybe the CERN people will build it under Geneva.
Do you see CERN as capable of accomplishing everything that would’ve been done at SSC, or are there things—
—that would’ve been done at SSC that even CERN never would’ve been able to achieve?
No. The SSC is a big difference in energy. There are things that may be in intermediate energy. It’s unknown, let’s put it that way. One doesn’t know. The difference in energy, is there new physics there? I don’t know, but the only thing I do know, up to now, the LHC has only mainly found the Higgs, which is a big thing, don’t get me wrong, but there’s no supersymmetry, there’s none of the other things. That may be there between the energies of the LHC and the SSC.
But when you say the physics are unknown, what does that mean?
Well, maybe these other schemes to supersymmetry, maybe all those symmetric particles are a factor of 2 or higher in energy than the LHC.
If money were no issue and the government decided to put 20 billion dollars toward a new SSC, would you support that?
Not clear. Not clear. Not clear.
Why the hesitation?
A little hesitation, because there’s a real gamble. Is the new physics higher than the SSC energy? Could be. There’s no landmark that tells me what the energy scale should be, so it’s a real gamble. If I had the SSC and know of nothing there, then I would say, well, we really are out of business, but it’s not known now, so I don’t know the answer to that.
Nick, I want to ask you about the decision leading up to your retirement in 1997. First of all, as director, obviously, you want to make sure that you leave the lab in the strongest possible position for your successor and for your own legacy and for what you had worked so hard to build over your decades there.
Where did you see the lab in terms of—was it on solid footing when you started to think about stepping down?
Let me go back a little bit. I became director in ‘82.
And, by ‘91, RHIC was being built. I’d done all the work to get the approval, the people, the construction was started. So, in ‘92, I said to the board, “I would like to step down after 10 years.” I thought 10 years as the director was reasonable. They said, “No. Stay on because RHIC is still in an early phase.” So, I said, “OK.”
And what’s the connection? Why did they want you to stay on simply because RHIC is still in its development stage?
Exactly, exactly. You know, the program had to be—the experiments had to be really fleshed out, make sure the construction is going to keep going, everything and so on.
So this is to say that RHIC is such a big deal that this is not a time when the board wants to see new leadership; they want things to be steady at the top?
Exactly. Right, exactly, exactly. So then, what I did was I said, “OK.” And that was ‘92. So, in ‘96, I told the board, “I would like to step down next year.” That’s ‘97, ‘cause I’d be 65. And I said 65 certainly is an age to retire. And one of my great heroes was Panofsky, and he retired at 65. So they said, “Yeah, but hold on because we’re going to change heads of AUI, Mr. Hughes. We’re looking for a replacement. We’ll let you go in one year, but don’t announce it.” I said, “Fine.” So it came ‘97 and I told the board in January, “I’m going to step down in June.” And then we had the problem of the tritium at Brookhaven. As you know, the reactor leaked tritium in small amounts, but the community was unhappy, politicians weren’t happy. It was a real problem, and, in fact, it was a bit turmoil. So, I said, “OK, I’ll step down.” But it turned out I would’ve been out anyway because people weren’t happy when the tritium thing happened.
And what is your understanding of exactly what happened there?
What happened was the reactor is a deuterated reactor so it’s not hydrogen—it’s deuterium, just not H?O, it’s D?O. OK?
So, when neutrons interact with the deuterium, they make tritium. So, in the water, in the pool of water where the rods are in the reactor core itself, there’s tritium in there being produced. And it stays there most of the time. But what happens periodically, you exchange the rods, you pull them out, and there are little droplets on it. And then they go down into a water pool in the basement. So, all the rods, before they’re shipped out, sit in that pool of water for a length of time. And, as a function of time, the tritium slowly builds up a very little amount, because it’s just these little droplets of tritium. We were measuring the water level, but not accurately enough. And what was happening, the pool water was leaking very, very slowly over the number of years. So, it was leaking into the groundwater under the lab. And, at a certain point, we realized it and we sunk wells and we spotted the thing, and it was not offsite, it was onsite, but people were just unhappy. And so that caused DOE, with their safety people, to start saying this is bad, this is bad. And so they had a problem and I certainly was going to go out, but I had offered my resignation before. So, that was the difficulty there.
Was it difficult for you to offer your resignation or the timing worked out where you were ready to step down anyway?
I was stepping down. I was going to step down five years earlier.
But the timing for me at 65 was going to happen. But, as I said, even if I didn’t, it would’ve happened.
How well developed was RHIC was during those intervening five years?
It really went well. I had gotten Satoshi Ozaki to build the machine, who was a very experienced guy who I knew very well. And I got my old pal, Mel Schwartz, to come back from Stanford and mold the experimental program at RHIC, which he did. And we had a good crew, and the construction was going well. And the machine was built, finished in ‘99, and started operating in 2000, and it’s been operating for 20 years and no problems at all. So, turned out to be a magnificent machine.
Now, when you stepped down, did you retain ties to Brookhaven? Did you still go in periodically?
Yes. No, no. What happened is my last act as director was to set up the RIKEN Brookhaven Research Center.
And T.D. became its first director. Terrific. And when I stepped down, I became his deputy. So, it was funded by RIKEN. Brookhaven paid my salary. And I and T.D., we molded the RBRC, which still exists today. And, after T.D. stepped down—he was director for five years—so in 2002, 2003 I became director, and I became director of RBRC for 10 years, and in 2014 I retired.
Now, what’s the connection between the original RHIC program and then RIKEN?
Between RHIC and what, RIKEN?
RIKEN is an organization in Japan. It’s like an NSF.
It’s got a huge budget, and it funds all sorts of science in Japan, very prestigious. And when I was setting up RHIC, I set up an advisory committee, international advisory committee including a Japanese representative and people from Europe, other labs, and so on. And during this stuff, the Japanese were interested in getting involved in RHIC, and so they became part of—they contributed the money to having a polarized proton capability at RHIC. And that was in ‘95. So, in ‘97, when I stepped down, Professor Arima, who was a distinguished professor in Japan, he said, “Well, why don’t we set up a center for nuclear physics, exploit new physics at Brookhaven?” I said, “Great idea.” And I signed the agreement. And T.D. was the first director, and RBRC, RIKEN Brookhaven Research Center, essentially got involved in hiring young theorists and experimentalists, and a computing capability. And, since its inception, it’s had 100 graduates. These are postdocs and physicists, nonpermanent positions. They come for two to three years and then they go. And they’re connected with universities. A real good thing, and they’ve been very productive, but it’s a research center which essentially helped exploit the physics done at RHIC.
What have been some of the key achievements both of RHIC and the RIKEN program?
RHIC, the main achievement was discovery of the quark-gluon plasma called the perfect liquid. It is a new form of matter which is like a liquid. People thought that—when we do RHIC, we change from nucleons to quark-gluons—that it’d be a gas. It’s not a gas, it’s a very, very low viscosity—one of the lowest viscosity things you have around. And now we’re spending years exploiting its properties. Its properties are it has a high vorticity, just spins and spins, and so it’s got very peculiar properties. And so, that’s a completely novel thing. But they’ve discovered lots of antihelium, antitritium particles. But the polarized protons capability demonstrated that the contribution to the spin of the nucleon, which was thought to be mainly of quarks and found to be only one-third quark, we found the gluon contribution is also appreciable. So, we’ve gone from the spin to the real properties of this strange matter. And, in fact, you could think of the quark-gluon plasma—if you look at the cosmic ray background radiation, which we observe, we go back, and we look at the early universe. We see these blobs. Now with the quark-gluon plasma, we’re going back and heating up—we’re going back to the Big Bang when there were no protons, neutrons, there were just quarks and gluons.
And it’s a new form of matter. And we get to see that by looking at the particles that come out. We can create what it looked like at the Big Bang. So, it’s very exciting. And there are all sorts of hydrodynamic properties and symmetries that are broken. One is looking at other symmetries like chiral symmetry, which it turns mass on and off, which is now being exploited also, looking for the critical point. You look at water, there’s a phase diagram with the critical point. Is there a critical point for RHIC for heavy nuclei? Well, there may be. So, the whole program, 20 years of operation.
Nick, I wonder if you can—
Let me comment about RBRC.
We’ve had 100 graduates, both postdocs and fellows and, of the fellows, or of all of them, of the fellows mainly, 80 or 85% have permanent positions in institutions around the world, in Japan, Europe, and the US. So, we produce forefront physicists who have become leaders in their various countries in physics. One, for instance, is the head one of the major laboratories in Japan, one head of the Frankfurt Research Center in Germany, and so on. So great productivity in both.
I wonder if you could explain a little, Nick, just so that people understand how big a deal it is. When you say you were a part of the team that discovered an entire new matter, what does that mean exactly and why is that such a huge achievement?
Well, I don’t know how to put it. When you discover quantum mechanics—take superconductivity, right?
You found some materials that become superconducting at low temperatures. You can run current through it with no resistance, and it took us 50 years to figure out why. Now we make a new form of matter, and we’re trying to understand what happened after the Big Bang when the universe cooled off. How did it cool off and how did we start from the quark and gluons to the protons that we’re made of? That’s the process we’re studying, how did we come about? The other thing we don’t understand also is how come we’re all matter and there’s no antimatter?
[laugh] Why would you think that there would be antimatter?
Because there were originally. Originally, everything was neutral then somehow something happened, and we’re matter.
And so the big question is what was that something?
Yeah. It’s some symmetry.
And this remains a mystery?
What do you think it will take to solve this mystery?
I don’t know. I don’t know. No. The other mystery is the big—you asked me what are the big things now. You see, in the Standard Model, we have all these quarks with their masses, right?
All right. And the electron is half of this, the neutrino is almost 0, the top meson is 165 GeV. No one knows why those masses—what they are. No one knows. There’s no Balmer series that tells us that.
What’s it going to take for us to get there, to understand this? Is it advances in technology? Do we need the next genius to come along that sees things that we don’t currently see? What gets us there?
I don’t know. I don’t know. I thought string theory would do something for us, but I don’t know. It’s gonna take some bright guy.
And maybe, maybe the answers will come from astrophysics.
What was the promise of string theory that, as you seem to have indicated, has not come to pass?
Well, it’s supposed to unify all the forces. I’m trying to recall. I think you have the magnetic force, the gravitational, the strong force, and the electromagnetic, weak—all of these have to be unified at some grand mass. And we don’t have a theory. There’s no grand unified theory. Einstein tried it. Heisenberg tried it.
Nick, how closely involved were you with people like Sam Aronson and Ephraim Fischbach who were working on what came to be known as the “fifth force”?
I wasn’t involved at all.
But you were aware, you were watching this from the sidelines?
Yeah, I read about it. I think it turned out to be incorrect. Yeah. Things like that come up and people push hard and think they find—that would’ve been an enormous thing. People looked hard for it and didn’t find it.
And so then, Nick, you said that you retired in 2014. I’m curious; have you remained active in the years since?
Yes. Until the pandemic, I went in two days a week. I have an office. I’m involved peripherally in the experiment at Fermilab, which is the neutrino experiment. And I give advice. People come and ask for advice periodically.
And what kinds of advice are they looking for from you?
Well, sometimes on personnel, on strategy. Brookhaven, fortunately, got eRHIC recently, EIC machine, and there was planning on that, the strategy on—they come on personnel periodically. You know, one wants to make a change and put someone in charge; what do I think about that person? And so forth. And young people come to me on physics periodically. So it’s a good situation.
Nick, I’d like to ask you a few broad questions that ask you to think about your career in retrospect. The first one is: You really came of age during a golden time in particle physics. You really couldn’t have been better situated; the timing couldn’t have been better for you personally in terms of all the exciting things that were happening on a really fundamental level in terms of discovery. So I want to ask you, looking back 50, 60 years, over the course of your career, what are some of the things that, when you started at Columbia, were really not understood in the field, and that today are truly understood where particle physics, physicists have truly mastered these areas of physics? What do you think is truly understood today that was a big question mark 50 or 60 years ago?
Well, first, the thing that came about that wasn’t appreciated was symmetry breaking, symmetry breaking, CP symmetry breaking, super weak, the electronic and magnetic fields were coupled, it’s electromagnetic and weak. The electromagnetic and weak forces are the same. They’re combined by Ws and Zs. That was not known. At least that was unified, electromagnetic and weak. It wasn’t appreciated. Parity conservation, parity non-conservation and charge violation, PC was not appreciated. It was discovered later, not known. That’s been found. All of the symmetry of particles was not—Fermi commented once, “If I could remember all the names of these things, I would’ve been a botanist.”
[laugh] He had a way of doing it. We learned a lot, but we don’t understand their mass, as I said, but we know things are simpler. There are quarks and gluons, and we understand how they interact a lot, but not completely. The chromodynamics is still not understood. So, a lot of the things—also, superconductivity had been discovered in 1905. It’s only after Bardeen–Cooper–Schrieffer that we understood some parts of superconductivity, how it came about, Cooper pairs and so on. So, a lot of things became clear.
Nick, so many of these advances, of course, have major physics and theoretical value. What are some of the advances that you’ve seen over the course of your career that have had—I don’t know what you would call—perhaps societal value? Ways that advances in physics have improved our everyday lives. What are some good examples of that?
Well, computing and electronics—modern electronics is quantum mechanics. It’s not simple—IR is equal to V. And so one has all these devices that we have. All of computing and communication is due to transistors and lasers, and a laser is a quantum mechanic thing. That was Townes. And think of the thousand things that lasers do. So, it’s had huge effects on—my friend T.D. likes to say, “We gave you quantum mechanics. What more do you want?” But I’ll give you an example. The experiment that was done to discover CP violation at Brookhaven involved equipment and an experiment that took three months of constant, 24-hour-a-day. About six years later, that same experiment demonstrated with one pulse of the AGS. One pulse did an experiment. And that’s due to the great increase in electronics capability.
You look at all your TVs, you look at the games, you look at every—electronics dominates us now. Lasers were Townes trying to study the ammonia atom—sorry, the molecule. Now, the thing that’s true is, with quarks and gluons, we don’t know how to apply our knowledge of that. With quantum mechanics, with electrons and atoms and things like that, we had lots of applications that came about at that scale, that quantum mechanical scale. The question is, we don’t know with quarks and gluons, how to utilize that knowledge. In medicine, people have built machines to do therapy, which comes out of science, of course.
Nick, I wonder if you can talk about some things that remain mysterious today that would’ve surprised you. If I had the ability to ask you in 1960, 60 years from now—
David, I mean, dark matter.
The thing that’s amazing is that, of the stuff in the universe, only 23% is stuff we can interact with. Dark matter, which we know from the galaxies, the rotating arms of the galaxies, there’s a huge amount of matter out there, because it has gravitational effect that we don’t know what it’s made of. And we’re doing experiments all over-looking for these elusive particles. In addition, more recently, because of the supernova stuff, there’s another thing called dark energy. The universe is not contracting, it’s expanding. And there’s something that’s pushing it, and people are looking at, on each of these forces, what are the particles that are responsible for that? And that’s 80% of the stuff. That’s amazing, isn’t it?
Eighty percent of the stuff we don’t know what the hell is going on or what it is, but we’ve seen the effects. So, you’re going to go to astrophysics. We see the effects there, but you want your machines—hoping you have enough energy to produce these buggers, these things so that you could see them. For instance, we know the Ws and Zs are responsible for the weak interaction, but it was great that, at CERN, we produced the W and the Z, and we know its mass and they exist. And we know the particles that existed for the weak force. What are the things that are responsible for dark matter or for dark energy, for instance? That’s gonna be a puzzle. And it’s astrophysics that’s showing the thing, but we’re doing experiments underground, XENON underground at Homestake, all over to try to find these things, WIMPS, whatever, axions and so on.
Are you surprised—again, in the way the I framed my question, if you’re thinking in 1960 what’s going to remain mysterious 60 years down the line, looking back—
I wouldn’t have thought it. No, I wouldn’t have thought it, either.
No. No. No. I would have thought something in the number of particles or knowing what the—I would’ve thought something like quarks or just something smaller than a proton, they may be composites. That I might’ve expected. What is the ultimate building block of matter? But not dark energy or dark matter. No way.
Right. Nick, what do you see as some of the remaining frontiers in particle physics? You mentioned before that young people, they come to you for advice. And so I wonder if some of those questions are about the kinds of things that people who are looking to pursue a career today in particle physics, if they ask you about your perspective on some of the things that remain to be studied and important issues that should remain part of the field, what are they?
Yeah. Well, I think one, it’s the neutrino physics I think is very exciting in a sense that there’s a matrix which explains the quark’s interactions. Quarks and CP violation in the quark, in the hadron sector. There’s also a matrix in the lepton sector. And the question is, is there CP violation among leptons? That means electrons, neutrinos, muons, taus and so on. We know there’s CP violation among the quarks that we see that K0 decay, but is there a symmetry violation in a leptonic sector? That is going to be exploited by the experiment at DUNE. The other question is, is the proton stable? In other words, we’re made out of protons, but does it die at some large number of years? What is the proton limit? How long does it live? Does it ever decay? And proton decay is an important thing. For instance, does the proton decay into an electron and a pi-zero? We don’t know. And so people are looking for proton decay. I think those are two fundamental things that I would be looking at. And also, all these searches for WIMPS, axions, all these things that explain what we don’t know in these other things like dark energy, dark matter, et cetera, et cetera.
So, it’s clear to you that there’s much work that remains to be done in particle physics?
You know, there’s a famous quote in the 1900s about some physicist who said, essentially, everything is known except maybe the last seven digits of some interaction; “all the physics is known” in 1900. A famous physicist, I forgot who. And he turned out to be completely wrong.
I would never bet about some crazy surprise. It’s because we don’t know so much. No one can write down a formula that gives me the masses of all these particles. Before quantum mechanics, we were doing series of spectral lines, and we had a Balmer series, a whole series, and we didn’t know the explanation of why these color lines appeared. Well, we got quantum mechanics, and, by God, the frequency of those lines was explained. Well, it would be nice to have an explanation of why we have these masses or what gives—we know the Higgs give rise to these masses, but why these masses? And how many neutrinos are there? Are there more neutrinos? Are there sterile neutrinos? People keep saying there may be. When you say “sterile,” it means you can’t see them. [laugh] OK? But we’re devising ways to do it.
Nick, you’ve made it clear how difficult it is to predict the future. I wonder, though, given all of your decades in service at Brookhaven, perhaps you could summon the power of extrapolation and you could give a sense of what you see as the most productive future for Brookhaven in the next decades looking ahead?
I would say for Brookhaven—well, eRHIC is the future right now, eRHIC and RHIC. And the other thing one has to do is to think that they presently have a synchrotron radiation source. It’s OK, but one may want to do something better. And so I think investing in accelerator technology, thinking of new ways to make electrons or protons go higher energies less expensively is worthwhile doing. And particle physics for Brookhaven would be astrophysics if not having the machines here but being involved in the latest big experiments. Brookhaven is involved in the LSST, which is one of the big experiments in astrophysics being built. So, I think pursuing experiments to explore the dark energy, dark matter thing in astrophysics with the biggest devices. So astrophysics should be a major thing. And you could do well by building strong groups to go to places to do the experiments. You don’t have to have the machine at your place, but you should have the capability to send groups to Chile, to Atacama to these telescopes there if you want to do astrophysics, or to the LSST when it gets placed. And also, to the next generation particle physics accelerator, wherever it gets built, to have a strong capability of experimental technique to exploit the physics that will be important in looking for these new particles, supersymmetric particles, et cetera, et cetera. I’m not as concise as—I don’t see the strength that we used to have in biology and chemistry.
Ray Davis did his famous experiment in the chemistry department at Brookhaven, at Homestake mine in South Dakota.
Right. [laugh] Well, Nick, I think for my last question, I want to ask you a more personal one, and that is: Hopefully, the pandemic will be over and you can continue going back into the office. What are your ongoing goals as you look to the future in your own career? What are the things that you want to remain involved in, and the kinds of advice that you want to give, and the research that you want to do?
I essentially want to be involved in the neutrino program, mainly the—I hope I live long enough, but the thing is going to come on in ‘23—no, not that soon—’30. So, I’ll be close to 90 to 100 years. [laugh] So I don’t know if I’ll be alive to do that.
What excites you so much, Nick, that you want to be alive for this?
The proton decay excites me. That would be—I made my life on finding, like, the omega and the baryon and even the neutrino electron scattering. Many of my experiments involved finding a few unique events. And that would be great if I could find proton decay with a few events. That would be—what would I trade? [laugh] I don’t know.
[laugh] Well, I hope you are around for it, because that would be just wonderful for you to see.
So, Nick, I want to thank you so much for spending this time with me. It’s a real treasure to be able to hear your perspective going back really to the beginning of so many of these issues. So, to have your insight and perspective over the decades is really such a wonderful thing, so I really want to thank you for your time today.
But you were right, I grew up at the right place at the right time.
That’s just luck. You really can’t plan for that. Columbia and Brookhaven were really—there was a time you should be at the Rutherford lab, right?
And that was the great time. You could always pick times that would be great. Fermi at Chicago at a certain time.
But I was extremely lucky, But, as my friend, T.D., says, “You gotta place yourself in different places to be able to be lucky.”
If you’re sitting on your ass in the desert, you’re not gonna be lucky.
So, you gotta do something.
Well, it’s been a pleasure talking to you.
Nick, it’s been great talking to you, as well. Thank you so much.