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Credit: Justin A. Knight
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Interview of Boleslaw Wyslouch by David Zierler on September 18, 2020,Niels Bohr Library & Archives, American Institute of Physics,College Park, MD USA,www.aip.org/history-programs/niels-bohr-library/oral-histories/XXXX
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In this interview, David Zierler, Oral Historian for AIP, interviews Boleslaw (Bolek) Wyslouch, professor of physics at MIT and Director of the Laboratory for Nuclear Science, and Director of the Bates Laboratory at MIT. Wyslouch explains how the laboratories have been coping during the coronavirus pandemic and he discusses the educational opportunities available for MIT students at the labs. Wyslouch recounts his childhood in postwar Poland, and he explains how his apolitical instincts worked well with his interests in science as a student. He describes his work at CERN, Saclay, and at DESY as an undergraduate, and he conveys his good fortune to be studying physics outside of Poland during the upheavals of the late 1970s and early 1980s. Wyslouch describes meeting Samuel Ting and the subsequent opportunity he made for Wyslouch to continue his research at CERN with Ulrich Becker, and the circumstances leading to his faculty position at MIT. He describes his work on the RHIC accelerator and the impact of Frank Wilczek’s work on QCD, and he explains his ongoing collaborations at CERN. Bolek reflects on his contributions to quark-gluon plasma research and the use of CMS for heavy-ion detection. He cites the quality of his collaborators as the most important ingredient in his successful research endeavors, and he describes his involvement with the LHC and why he will always consider CERN his “mother Lab.” At the end of the interview, Wyslouch assesses how ongoing advances in technology, and in particular, computational techniques and algorithms, will continue to push forward fundamental advances in nuclear and particle physics.
Ok This is David Zierler, oral historian for the American Institute of Physics. It is September 18th, 2020. I’m so happy to be here with Professor Boleslaw Wyslouch. Thank you for much for joining me today.
OK, Bolek, so to start, would you please tell me your title and your institutional affiliations?
I am a professor of physics at the Massachusetts Institute of Technology, and also the director of the Laboratory for Nuclear Science, and director of the Bates Laboratory here at MIT.
And when did you assume the directorships of both the Nuclear Science Laboratory and Bates?
Laboratory for Nuclear Science in 2015, and Bates in 2018.
Now, are both the Laboratory for Nuclear Science and Bates, are they located within the Department of Physics or are they their own programs?
They are within School of Science. The way MIT is organized is that departments focus mostly on academic issues, on faculty hiring, and basically guiding physics program, whereas laboratories are organized to support the research and help researchers do their stuff. This actually works pretty well because we are optimized to support nuclear and particle physicists, whereas the laboratories that support chemistry activities, and condensed matter, biology, etc., they have different needs. Different resources are needed for this type of things.
We focus on supporting fundamental particle and nuclear physics, both in experiment and in theory. And Bates, it used to be a DOE-supported accelerator lab. It is actually about 20-something miles north of Boston. It was a linear accelerator that was doing a lot of nuclear physics, starting in the ’60s, all the way until 2005.
In 2005, the science operation stopped, and the lab was converted into engineering support lab. We do projects for particle and nuclear research at various laboratories around the world. There are engineers, technicians who can build things. We also have a computing farm there. In terms of scope of activities, it’s very, very closely related to LNS. There are some administrative historical reasons why there’re two separate directors. But, effectively, it’s just one and the same thing.
And given how hands-on the work in both is, I wonder how well you’re dealing with the pandemic right now?
We are doing actually reasonably well. The main reason is that, somewhat counterintuitively, most of our experimental work is actually far away at faraway research labs. So we are affected by how the faraway labs are reacting to the pandemic. For example, we have a large contingent of people at CERN. CERN was shut down for a while. They are opening it now.
The Large Hadron Collider was not operating due to its long shut down: anyway. So this did disrupt and slow things down, but it did not disrupt data-taking. The Brookhaven National Lab was actually able to restart accelerators, even during pandemic, so some data was being taken. At the lab, we have few people coming to work. We have some faculty, postdocs and students now working with R&D, develop detectors, etc. They are able to come and do their stuff.
Bates is able to operate right now at 100% because it’s a very large place with relatively few people, so there’s plenty of space for social distancing, etc. So we are affected, but not as much. One thing which we did which was really important is we—from the day one—we decided to keep all our computers running. We made a big effort making sure, especially that we have a very large computer farm at Bates, that this was maintained and operated throughout.
A lot of our people are doing remote data analysis, designing detectors, doing simulations, doing theoretical work, and this was able to continue from a technical point of view fine. Of course there are psychological effects, people being isolated, but we tried to keep everybody engaged. So it is a bit of a slowdown but not a dramatic effect.
Bolek, given your administrative duties right now, I’m curious if you’re able to keep up with teaching at all?
Actually, I do not teach. As the LNS director, I’m excused from teaching, so I do not teach. However, I try to participate in educational activities of the department as much as I can. I sit on exams, and I also do a lot of database work. It is my hobby, I develop databases for the physics department, my experiments, and such things. I contribute to
—educational mission, but I do not teach.
What about graduate students? Do you take on graduate students?
I graduated several of them recently. At this moment, I don’t have any. But, you know, I’m right now trying to work on a new upgrade project for CMS, the detector at LHC, and this project has not started yet full-blast, so that it’s too early to have students for that.
In terms of your educational interests, Bolek, I wonder if you ever have opportunity to include undergraduates in your work, both at the Laboratory for Nuclear Science and at Bates?
There are large numbers of opportunities for undergraduates. MIT has a very effective program of bringing undergraduates into research. It’s easy. Financially, it’s inexpensive. There are all kinds of discounts for employing undergraduates.
At the lab have very many undergraduates, and they go out to Bates and they work on campus. Yes, this is a big thing. When I was doing experiments at CERN or Brookhaven, we had lots of undergraduates working with us. And they’re still working with the group, yep.
Let’s start all the way back to the beginning. Tell me a little bit about your parents first. Where are they from? Are they also from Poland?
I grew up in Poland, I was born still in the 1950s [laugh] at the last moment. I grew up in 1960s, 1970s. I went to university around 1977, and this was actually an interesting time. I come from an academic family, a well-educated family. My grandfather was a professor. My father was an engineer.
My mother—actually, practically all the women in my family across multiple generations have PhDs or other advanced degrees. [laugh] My sister, my cousins, many people in the family have PhDs. We come from a long tradition of education, academia, and in general contribution to the society. My father was a mechanical engineer, so I spent my youth going and visiting his prototyping factories, driving road-building machines at the age of 12. My parents divorced, and my stepfather was a professor of mathematics. I was very influenced by the combination of the two, I managed to maintain a very good relationship with both sets of my parents for many, many years.
And it was an excellent combination that actually got me into where I am right now. I had a stepfather who was a mathematician, very theoretical, very involved with young people, so he was constantly prodding me, asking me questions, and we solved problems all the time. And I had my father, who was very experimental, able to build things, etc. And I was maneuvering between them, and somehow in high school, I discovered that, physics was a combination of the two. On one hand, you were asking fundamental questions. On the other hand, you could build things.
I didn’t completely understand it in high school how it all works, but this was somehow how I was driven towards physics. I remember in junior year in high school, I don’t know how, completely by accident, I bought The Feynman Lectures of Physics. I just went to the store, bought some books. I had no idea what you kind of book it was. I didn’t know about the world that much. And I bought this book, started to read it, fell completely in love with physics, thought that this is really fantastic, and I learned a lot. Most of my intuitions in what I teach in introductory physics come from that reading of that book at that time.
It’s really interesting. And then I tried to decide what to do after high school. You had to choose your university. And also through some coincidence, I decided to study physics. I decided to go to Warsaw the capital, instead of staying in my hometown—
Which was where? Where did you grow up?
The city was called Wroc?aw, which is in the western part of Poland. It was an interesting city because this was in the part of Poland that was taken over from Germany. So everybody in the city was basically an immigrant newcomer. The families lived in eastern part of Poland, which is now Belarus, Lithuania. And in 1946, ’47, they were all put on trains, and just moved to the west.
Were there ethnic Germans as well, or did they all leave?
They all had to leave. This was ethnic cleansing of monumental scale. They moved several million people in very tough conditions. Every single German had to evacuate the city, and then the Polish people moved in, and just started, you know, rebuilding and building things, etc. It was an interesting development—the society was very mixed.
You had people of different background. Also the new social system was being introduced at the same time. So we had a very mixed, very diverse neighborhood, diverse group of people in the school with very different backgrounds. They were all Polish but with very many different social and economical backgrounds.
And, Bolek, I want to ask, particularly because you grew up in such a scientific household during this time in the Cold War, were you ever made to feel like pursuing science was something that had to be done in the service of the state?
Oh, it was the opposite. [laugh]
Absolutely. This was not an issue. In Poland, this was not an issue. Actually, you would do science to avoid collaborating with the state. This was one place—physics, math—these were subjects where you did not have to be part of the nomenklatura. You didn’t have to be a member of a communist youth organization, etc.
So there were quite a bit of people who moved into those areas who were—who just didn’t want to deal with politics, or wanted to have some freedom. At that time, politics was rather soft, we did not feel that oppressed. Poland was quite open during the time, especially when I was in high school and at the university. This was the time, when I was at the end of my studies, the Solidarity movement broke out, and so there was quite a bit of freedom.
Personally, I was able to travel, I was traveling outside of Poland quite freely, and we had contacts with people from outside. We were able to talk to people. We had lots of visitors. So the country was really opening up at that time. And it also helped my career as well.
Now, in terms of focusing on a field of discipline at university, do you declare the major in physics right away, or is there a general education component, and then you settle on physics?
No, physics you declare immediately. You have to choose. At the end of high school, you have to choose where you want to go. I tried to choose between mechanical engineering at the local technical university, and physics at the university in the capital. And I decided to go in the physics direction. Actually the reason was, it’s crazy, but there were olympiads, physics, math olympiads—
—I participated in the physics one when I was a junior in high school after reading my Feynman. And I managed to get to the national level, and I completely failed over there. I didn’t get anywhere. But the trick was that if you got to the national level, you were excused from entrance exams to physics. But if you wanted to go to—let’s say—to mechanical engineering, you had to take exam. You were excused from the physics part, but you had to take math and then the language, and so on.
And I knew that I could have trivially passed the entrance exam in math, etc., but somehow it got me thinking, you know, why not I just go where it’s I don’t have to pass any exams? And it got me thinking about the whole idea of studying physics. It was completely not part of my plan. But because of this particular administrative advantage which I had, I finally chose to study physics, and I took my driver license exam instead. So all my friends were passing exams to university, and I took my driver license exam. [laugh]
And then I went to study physics, and this was really a good choice for me.
Bolek, given all of the social and political upheaval that was happening in Poland while you were an undergraduate, I’m curious if you were politically active at all yourself?
The answer’s no. All my friends were involved, so there was a lot of activity around. When I was at the university, there was a formation of an independent student union. There were strikes. There were all kinds of things. And I was distinctly not interested. I was very supportive of it. I absolutely did not support, you know, the government and so on. But I just thought that this is not me, you know. I like to do my little things in the corner. It was not me to go and, you know, give speeches at meetings, etc. And many of my friends, many of my cousins, many of people in my family were active, but I was not. And a lot of these activities were happening during summer vacations.
And I had some very important things that happened to me during summers during my undergraduate years which—again—got me where I am right now. Because Poland was opening up, students and other young people tried to get a job somewhere in Western Europe, a summer job. Through a colleague of my stepfather, some connections, we got a pretty good deal in Germany. I and my close friend went during the summer to Germany. We worked as gardeners. We did some cleaning work in some chemical company somewhere.
And we made some money, and then we went hitchhiking through Europe, all over the place, Holland, London, Paris, etc., all hitchhiking. And part of this hitchhiking brought us to Geneva, Switzerland, in addition, our sponsor from Germany found us some job in Switzerland, painting job in a factory. I learned how to paint, which is always very helpful. On the way to that Swiss job, we stopped in Geneva, and we stopped on Saturday, we went to see CERN. CERN has visitor tours.
They put us on the bus. They drove us to various places. And I absolutely fell in love. I mean, this was—you know—I remember like today, this was it. And they showed us some experimental halls. There was this big machinery.
All nicely painted. And all I remember from this visit were “wire chambers”. They were working on wire chambers. All right. Then we did this painting job, went back to Poland, went back to my university. And we discovered that there was a group in Warsaw that is building wire chambers for CERN.
There was—at CERN, there was a guy named Georges Charpak, who got the Nobel Prize for discovery of wire chambers, and he was originally from Poland, he had these collaborators in Warsaw who were working on wire chambers. So me and a friend, we just walk into somebody’s office, and say, “Look, we would like to work on wire chambers.” And they say, “Yes, why don’t you work with us on wire chambers?” And in Warsaw, undergraduates working in research groups were not common. This was rather unusual. But we wanted it, so we just started work with wire chambers.
So I learned some programming and, you know, did little bits of research. And then during those—once we started hanging around those labs, a professor came to us and said, “Look, there is a summer program in Germany in Hamburg. It is DESY laboratory. And they are—they have a summer student program, and they would like to open it up to Polish students. So it’s the first time this is happening, first year. Why don’t you two go to Germany to that—this summer program?”
All right, so in the summer of 1980, we packed our bags, and we went to Germany to—for the DESY summer school. And it was, again, fantastic. For two months, we were working with some of the best experiments in the world. This was the leading, highest energy accelerator. I got to do some cute things on a computer, I loved it. I talked to people.
After this, I was absolutely convinced that this is what I want to do. Within physics department, you had to choose your specialty. The summer stay gave me a picture of the world of high-energy physics. I met a lot of people. After two months, we went back to Poland to continue our studies.
The summer of 1980 was the summer of Solidarity. So we—I remember—we were in Hamburg, and we were watching television with strikes in Northern Poland, in the shipyards, Lech Wa??sa, and so on. And, for me, this was a very [laugh] good situation, I was doing my physics—
—as well I could do, you know, and at the same time, my country was improving. So I looked forward to the better life in Poland. And my idea was to continue physics, get a job at some university in Poland, and then continue collaborations with labs, you know, DESY and so on. We went back to Poland. I also decided to switch advisors, this was my last year at the university.
I was supposed to do some sort of master thesis. And my advisor at that time had experiment at—was a part of experiment at CERN, so he sent me to CERN. So in the summer of 1981, I went to CERN, and this was again an unbelievable experience. We had a group of about five, six people. We had our own detector. We’re putting it in different accelerator beams, taking data, each of us was responsible for something.
I was doing an interesting project, making all kinds of mistakes, In addition, CERN has a summer student program. There are hundreds of students from around Europe who are coming and working together. So this was—again, scientifically and socially—was unbelievably a good experience. Again, I met a lot of people. Many of them that I met at that time are part of the high energy physics community.
Bolek, I wanted to ask, even as a student in the late 1970s and early 1980s, given your exposure at both CERN and DESY, what did you feel at the time were some of the biggest questions that were being asked in high-energy physics at that point?
Interestingly, I remember at the very beginning of my studies, it was ’77, ’78, when I started to learn about things, I remember once talking to somebody. I went for a date. And I remember explaining the November Revolution. And the quarks, the colors, all the—you know—the—this new understanding of particle world, etc., that happened in November of 1974.
Had you met Sam Ting at this point yet?
Not even close
I had no idea. But I remember—imagine Warsaw in 1977—you talk about November Revolution. And I distinctly remember how excited I was. And so this was really—this was beginning of QCD. This was beginning of the Standard Model. This was—people were making measurements which were—you know—now we consider really fundamental.
And you had these new accelerators, new detectors coming up, and giving data. So at DESY, I worked on e+ e- collisions. My job was to count the number of charged particles, the charged multiplicity. And I was sitting in front of the screen, and counting how many tracks were coming out. And at CERN, I worked on the neutrino-scattering experiment, which gave one of the very first measurements of strong interaction coupling constant.
And I’m not sure I knew how fundamental this was, how important it was. But you could see lots of other people were very excited about things. I just went with the flow. But, let’s get back to the summer of ’81. We are doing this detector experiment, great, and I was three months at CERN.
From CERN, because of various arrangements, financial reasons, I moved for three months to Paris at Saclay. I was supposed to sit there, analyze the data, and write my thesis, go back to Poland, and defend my thesis. And then I supposed I would get a job at a university because I was doing well.
And what was the project at Saclay?
So this was a measurement of a calorimeter. I was supposed to calibrate the calorimeter. There was a hadronic calorimeter for CDHSW experiment, led by Jack Steinberger, and this calibration procedure was supposed to improve the resolution of the calorimeter.
And it comes December 1981—13th of December. I’m in Paris. Through my stepfather’s connections, I had a usage of a small flat in Quartier Latin. It’s a weekend. I’m having a lot of fun. On Sunday morning, I wake up, I switch on BBC, and the news are that there is military law that Poland has introduced.
There are tanks in the streets. The phone connections are cut off, etc. And, whew, this was tough. I had no idea. I was, you know, 22 or something, and I had—you know—my world just, poof, collapsed. I had no idea what’s going to happen.
This was really tough. And I remember, it’s dark, December Paris, the rain is falling, and I’m going to Polish embassy. There are some people with flags. There are governments issuing proclamations and all kinds of things. But I completely lost contact with my family. I had no idea.
For like a month and a half, I had no idea how they are doing, what’s going on, etc. And the first news which I got was a postcard from my mother, who wrote me “You should stay, work on your thesis [laugh] as long as you can.” [laugh] OK. I later learned that my father was actually interned, a couple of my cousins were in jail, and going back did not sound good.
And for what? Just for general political activity? What were they in trouble for?
That’s correct. What they tried to do is they, the government at the time, basically they identified the people who are troublemakers, maybe 10000 of them, and they put them into so-called internment camps. They basically separated them from the society so that things could calm down. The best way to separate people, just put them into jail. So they emptied jails from the criminals, and they just put all those people.
The people who were active politically ended up in—for a couple of months—in jail. And so my father went to jail. It’s a longer story. And I had no idea what to do.
So I’m sitting at Saclay. They treated me very well. They extended my contract. They increased my salary. They just gave me a few more months of staying there so I was just working. But I just couldn’t work.
I mean, my thesis was not progressing. I was really upset. And after few months, I went back to CERN because they couldn’t keep me in France. At that time somebody was giving me some money for something. I don’t know exactly how this was arranged, I was getting some money at CERN. The people were helping me, and I was just sitting at CERN trying to decide what to do.
I was working on some new hardware project, trying just to survive. But I had no idea what to do. In addition, I did not have my undergraduate degree because I would have to go back to Warsaw and to defend the thesis.
One day, it’s late spring, early summer. I’m sitting in CERN cafeteria, and I’m sitting with a colleague, a Polish guy from DESY whom I met during my summer school at DESY. And Sam Ting and his group was passing by. They were at CERN, proposing a LEP experiment at the time.
And my colleague says, “You know, Bolek, this guy wants me to work for his experiments, I know him well. I can talk to him, maybe he has a graduate student position for you.” By then I then heard all the stories of how difficult it is to work for Sam Ting, and that he has a very good group but a very tough group. I heard a little bit about MIT but minimally.
I had no choice. I said, “Yeah, go talk to him.” So my friend, Henryk Kowalski, went to talk to Sam Ting. Sam Ting calls me in, and I walk up to him, and I said, “You know, [laugh] I would like to be your student.” What else can you say? [laugh]
And they did—they gave me some exams. I remember I took a physics exam in CERN cafeteria. I took electronics exams in somebody’s lab. And after that, Ting tells me, “OK, you can come to join us but in DESY in Hamburg.”
So then I—you know, the visas, the passports. I had a complete mess with my visas and passport. But somehow I managed to arrange it, I went to DESY for a year. And at some point, somebody brings me a piece of paper, says, “Fill it out.” So I filled it out, name, etc. This was application to MIT Graduate School. They accepted me at MIT without my undergraduate degree, I still didn’t have my undergraduate degree, and I started work for them.
I went to MIT in Cambridge, did my courses pretty quickly, went back to DESY, worked for the Mark-J experiment at DESY. There was accelerator, PETRA, the e+e- collider. It stopped running in 1986. Sam Ting wanted me to start looking for a job. So I’m working as a graduate student, working hard, doing my things. One day the door opens, and Sam Ting comes in and say, “It’s time for you to think about your other job, you’re about to finish.”
He says, “I can talk to my friend, Burton Richter, at SLAC. He can give you a job, or you can work with me.” I went home, I was already married at that time. I asked my wife, “So what do you prefer, California or Geneva?” And she says, “California, earthquakes, no way.”
Next day, I go to Sam Ting, I tell him: “Geneva, easy.” Why should I spend more time thinking?
Bolek, at this point, I want to ask, is this—are you looking at this as your ticket out, that you won’t ever have to deal with the problems in Poland as long as you were able to continue on this path?
Oh, absolutely. The whole issue of passports and visas and permissions, this was always hanging over me. This was something that took a very long time to get rid of. So quite a bit of my decisions of how to go and where—were often taken because, this was a practical way forward. But I was just incredibly lucky. I was just unbelievably lucky that those decisions, practical decisions happened to be also the best possible, decisions in physics and science and so on because—I’ll tell you.
I chose to continue to work for Sam Ting, supposedly because of earthquakes in California. We moved to Geneva. I worked as a postdoc for L3. The accelerator in California was supposed to start much earlier than in Geneva. They had some technical difficulty. It got delayed.
People who worked on that project at that time had to spend about two years waiting for the accelerator. They were doing a lot of simulations, physics studies, etc. Whereas in Geneva, I was working on building the detector, and assembling things. And it just happens that I am much better in assembling things and building detectors than I am in doing physics studies. So if I would have gone to California, I would have just completely burned out, and I would not stay in the field, I think—this would have been a wrong scientific decision for me. I was very lucky that I went to CERN.
And at CERN, I really had a very good time. I worked with my advisor and direct supervisor Ulrich Becker, who unfortunately very recently passed away. And he was an unbelievable scientist, fantastic human being, a fantastic mentor. And working for him and his group was incredibly satisfying.
And what was his research? What was he working on when you got to know him?
He was part of the original J/psi group. He was working with Sam Ting’s group all his scientific life. He was part of the research on J/psi. He was on all the experiments. And his contribution was that he was a very gifted detector-builder. He was building detectors, mostly the wire chambers, that were specifically designed and optimized for the physics tasks.
He had a very good understanding of physics, and he was able to build detectors that would produce good physics. It was really interesting to see because you had lots of different detector technologies developing at that time. The physics is, of course, driven by improvements in experimentation. There are many, many new ideas for detectors, they are being built, and physics advances with new technologies. There are people who are focusing on building—just building new technology. They just have a cute type of detector, push its performance, they try it, they test it, and so on. Becker was doing similar things. He would also work on a certain type of detectors, trying to improve them. But he always had physics in mind. So those detectors were always designed, always had to work, always had to contribute to physics. And this was the extremely important thing which I learned from him, his attitude to detectors. In his group, I was in a good position, I was leading a team, I was doing detector testing. It was a very good experience for me as a postdoc with that group in Geneva.
Bolek, I want to ask at this point as you’re starting to solidify your own identity as a physicist working professionally, what were you discovering about yourself, both in terms of the things that you were interested in, and the things that you were specifically talented in?
That’s a good question. I—I’m not exactly sure.
In other words, in a collaboration, everybody brings something unique to the table. So, as you were working at this level, what were those things that you felt like you were able to contribute?
Yeah, I think I can see the goals, and how to get to the goals. I can see the path of getting to the goals, how to arrange things, how to schedule things, how to—you know, what is important, what is not important. So I’m often able to push for things which turned out to be important later. I was several times in a position of a manager, project manager. And I knew what needs to be done to arrive at the final conclusion, the prioritization.
I think a lot of it comes from my observation of how Sam Ting’s group worked. There were many people in that group who were very focused on making sure that the measurement can be done, so you had to do things, you know, you had to spend time, you had to prepare, you had to practice, you had to test. And so I saw how you get equipment to be operational at the right moment, at the right time. I was put in a position of leadership on a small group. And I was able to push them or to lead them into reasonable conclusions. And that’s probably what it was.
Now, am I expert in specific type of detectors? I don’t think so. I must say that I’m not very good in data analysis at the—you know—at detailed level. I do not have patience to really follow the propagation of errors, etc. I do not have patience for that, so I’m not very good at that. But I know who can do it, so I can talk to the people who know how to do it, and help them as much as I can too, so that they function well, and deliver results for the group. So that would be how I do things, yeah.
I assume at some point you recognize that you’d need to go on for your PhD if you wanted to continue to grow in this field.
I never thought much about it. That was—you know—that’s what people did around me. PhD was a default step in my career. The real question was where to do the PhD? The default solution was to get a PhD in Poland. After PhD, people used to go for two or three years projects as a postdocs in some foreign laboratory or at other university.
It never occurred to me that I can apply for PhD programs somewhere else. And it was only at DESY during lunch, there was a professor from Cornell, David Cassel, who was on sabbatical there, and he said, “Look, you know, you can go to the US for PhD studies. And, by the way, this is the list of universities.” So he took a napkin, and wrote a list of universities, and I think—I’m not sure if MIT—I’m sure MIT was on the list. [laugh]
But, so this idea that you can actually go to—and get your PhD abroad was first time that it occurred to me. I just had no idea it was possible. Again, those chance encounters gave me ideas of how to move forward, yeah. And here I was at CERN, with a PhD from MIT, just working on the detector, very happy with my detector work, leading my team.
And one day Ulrich Becker comes to me and says, “You know, Bolek, you should do some data analysis.” I say, “How? Me, data analysis? I have no experience. I don’t know how to use those computers, you know. What about the cables?”
And he’s, “No, somebody else will do the cables.” So I was one day, from one day to another, I was supposed to go and do analysis. All right. I go start doing analysis, and I got involved in analysis of Z decays into b-quarks, I made measurements for a year and a half. And then Sam Ting comes to me and say, “Do you want to be professor at MIT?” “Me, professor at MIT?”
“What are you talking about? I’m here doing cables?”
[laugh] I’m not joking. It was really like that. So I go home. I don’t—maybe I first went to Ulrich Becker and say, “Sam Ting is talking about me becoming professor at MIT.” And Becker said, “Of course, why not?” Fine.
So then I go home. I say—I ask my wife, “You know, they want me to be professor at MIT.” She said, “Great, yeah.” So next day, I come to him, “Yes, I want to be professor at MIT. But what do I have to do?” [laugh]
And then some process starts. I have to apply. I go for an interview. I didn’t apply anywhere else. I have no idea what does it mean to—you know—to apply to a university. I got an offer, and the colleague from MIT, my dear colleague, Professor Wit Busza was the chair of the committee.
He calls me in, says that I was offered the job. And so I go home. I ask my wife, “Should I take the job?” She says, “Yes.” Next day, I call back MIT and I said, “Yes, I accept the position.” It took me less than [laugh] 24 hours to accept.
And nowadays, you know, when a faculty accept these days, they take months to accept, then there’s startup funds, there is all kinds of negotiations. I had no idea. I just accepted. And so that’s how I became a faculty at MIT, continuing working with Sam Ting. And then about two years into my position as a faculty, I started to think, oops, I finally understood what it means to be a faculty at the university, especially at MIT. You really have to run your own shop.
And also, by that time, LEP was very successful, it was taking very high-precision data. And the physics morphed into doing very, very precise measurements. And I just wasn’t very good in that. I just didn’t have patience to really dig out, you know, uncertainties and corrections.
I had lots of friends who were very good at that, and I just—it just wasn’t my thing. I went through a difficult period where I really had no idea what to do. And was a second-year faculty at MIT.
And what is your title at this point at MIT? Instructor?
I was an assistant professor.
I was an assistant professor, and I was on the tenure clock, so I have a certain number of years to prove myself. And I started to think, and it just—you know—I’m not doing very well. I don’t know what to do. I’m not very effective. I’m not very happy, etc., so what do I do? I started looking at other options.
At that time many physicists were going to Wall Street. My closest friend was doing very well there, so I thought, maybe I can use this in case I failed at MIT. But, I really had lots of doubts, and I just did not see myself playing any leadership role in the Sam Ting’s group, etc. I felt like I have to do something. I was talking to various people. One thing which is—was always important to me, I liked to talk to a lot of people to ask for advice.
I spent a lot of time talking to people—that’s how I grew up. I talked to my father, to my stepfather. I asked them for advice. They usually had very different advice, so I was able to choose my own. During every step of my career, I had lots of very good advisors, and I was very careful in going around and asking. So I started to go around and ask, and talk to different people, you what are the possibilities in life for this second [laugh] year assistant professor at MIT?
And it was clear to me that you had to have your own thing, and you had to have something done to have any chance of being promoted. One day, I walked on a lawn at MIT, and I bumped into my colleague, Wit Busza. I talked to him a lot because he is also Polish and we could speak Polish. I told him that, I’m very worried about my future. I don’t know what to do, etc. And he says, “Look, I have this project in heavy-ion physics, and I’m looking for somebody to play a role in that.”
I looked at him and wondered: “Heavy ions? I have no idea what you are talking about.” I knew nothing about it. But I told him, “Look, I give you half an hour to convince me.” So we go to the office, and here tells me an exciting story.
There’s this new accelerator called RHIC, which is under construction. MIT has a new experiment. We are going to measure charged particles, (which btw, was my summer project back at DESY). And the experiment needs somebody to take care of the building the detector. They need a project manager to build the whole thing.
And I thought, wow, that sounds interesting because there is new physics, completely new accelerator, completely new ideas. You don’t have to measure anything precisely because nobody knows what to measure. Well, they knew, but not as precisely as in high-energy physics. And then there’s the detector that needs to be built. It is about to start, so it sounded like an interesting opportunity.
I then started to walk through the department, went to the department head, to the lab director, the dean, and I told them, “Look, I would like to switch fields.” And this was two years into assistant professor “clock”—one has about four years to produce some good results, and about six years to have final results so you can be promoted to tenure. And they told me there’s just no way. You are crazy to switch it.
Why? Why would they say that?
There’s not enough time. Switching to a new field, there’s just not enough time.
Yeah. This was the consensus advice that you got?
This was the direct advice, but they also said, that of course I can do anything I want. They were very supportive. But this was just crazy. Also, there was a question about Sam Ting, how will he react, and so on.
And, by that time, I almost couldn’t talk to Sam Ting. I was so afraid of him. And of course, I was doing all these decisions while thinking about my salary, passport, all those kind of things, stability. This is always something that worried me that if I fail, I have to go back to Poland.
I had to be careful about practicalities. By that time, I had a family, I had a young son, and so on. However, I discovered an interesting thing. I talked to the department head, Ernie Moniz, and it turns out that, yes, there’s a tenure but there is also some job stability spanning several years. He told me that from that moment, I had guaranteed three years of salary. Whatever happens, if I fail or do something, I had three years. And I took this as an important stepping stone. So, OK, I have three years. I can do anything I want.
So I decided I’m just going to use my three years and then, if it doesn’t work, I had time to find something else. Also, this was the moment where I decided I’m not going to get tenure, so I don’t have to worry about it. I have my salary so I can do anything I want. And it was great. It was very liberating at the time. [laugh]
And then things started to really move very quickly. I became a project manager for the new RHIC experiment. This immediately put me up for discussions with Department of Energy, with other spokesmen of RHIC experiments, I started very quickly to learn how the system operates, how the accelerator’s being built, how to build detectors. I had a team of people. I was extremely well-prepared technically for that. I worked for Sam Ting’s group for 10 years, so I could very quickly make technical decisions.
I ramped up as this—into the group very quickly. I was extremely motivated. I was liberated. It was fantastic. The team was great.
Wit Busza was an unbelievably good leader of this whole effort with very good people. From one day to another, I jumped into the project. However, the accelerator construction got delayed, I couldn’t get any data from RHIC. We started talking of what can I do in between?
There was a very interesting physics idea being advertised by Frank Wilczek about QCD properties which could be tested in heavy-ion collisions with certain detectors. I thought, why don’t I look into that? The highest energy heavy-ion accelerator which was running at that time was at CERN. They were supposed to get new beam of Lead ions. So I looked into the book of experiments at CERN. Which one can do this particular measurement?
I found one that could potentially do it. It was called WA98. I called some friends. I called the spokesman of the experiment, Hand Gutbrod, and I said, “I’m interested to do some measurements with you. Can I come next week [laugh] to CERN?”
He said, “Sure. You should join me.” After CERN visit I went back to MIT and I bumped into Bob Birgeneau in the Infinite Corridor at MIT. Bob was the Dean of Science at that time. And I told him, “Look, I have this new project, but I need some funding for travel and everything.”
And in the corridor, Bob told me, “Write a one-pager for me by this evening.” I wrote the one-pager. Next day, we met with a funder. Within 24 hours, I got funding for my new experiment.
Bolek, what did you write that was so compelling to have it approved so quickly, do you think?
This was a very interesting idea of Frank Wilczek that in QCD, if you go to somewhat higher energies, the u and d quarks become identical. In normal hadrons, the u and d quarks have slightly different mass, so they’re not symmetric. They cannot be completely exchanged. But if you go to higher energies, they’re really identical. It’s called isospin symmetry.
And the idea of Frank Wilczek was—and Krishna Rajagopal, his student— that if you collide the heavy ions, you excite the QCD vacuum, and then, as it freezes, the ratio of u and d quarks does not have to be the same as in the regular matter. There could be a spontaneous symmetry breaking in a different direction than in the usual matter. So you may—could produce way more u quarks than d quarks, and so on. And u and d quarks are the components of pi mesons.
So you have a π+, π-, π0. And you could have events in which there are way too many π0 than π+, π-. Typically, you have one-third, one-third, one-third. But there was a hypothesis that, in principle, it’s possible to produce events in which you have way too many of one versus the other. So you had to make separate measurements of charged pions, and neutral pions. The new type of matter was called disoriented chiral condensate.
And the hypothesis was that this could be a really very important—this is a very fundamental property of QCD. So if somebody could find collisions, events in which there would be a big imbalance of those particles, then it would be an indication that those type of objects are created. And, at that time, we quickly did—you know, me and a student did quick literature search that showed a that there were no experiments that measured separately neutral and charged particles in heavy ion collisions.
However, there were measurements in cosmic ray experiments. There were indications than in some cosmic ray collisions, as measured using emulsions, there were events that had unusually large fraction of either neutral or charged particles. At CERN accelerator and with new beam, there was a detector that could measure, in principle, neutral particles and charged particles separately. So we joined that experiment, and tried to do this measurement.
It turned out we haven’t seen any signal of this physics. It took quite an effort, actually, to make this measurement. But it was an interesting project, several of us from MIT worked on this project for a couple of years. We made measurements. We obtained limits on the production of this thing, and it was nice.
And, Bolek, how frequently were you interacting with theorists? How much was that an important part for your collaboration in this area?
In that particular project, there were many conversations.
I mean, was Frank—were you talking with Frank a lot during this time?
Not to Frank. I was talking to Krishna Rajagopal a lot. It was his PhD thesis at that time. I think he started at MIT or he was planning to come to MIT. This became a very hot topic in theory of QCD at that time.
There were many theorists who were working on it. There were all kinds of issues with this phenomenon and the measurements. So yes, I spent a lot of time talking to theorists.
And I want to ask also—at this point, it seems like this is a bit of a narrative turning point in your career where you’re moving away from not being sure how everything is going to turn out, and starting to sense that, you know, this is really coming together for you. So, you know, in that light, I wonder if you can talk a little bit about—going back to this idea that seeking advice and having mentors has always been important to you—maybe you can talk a little bit about what you learned from Sam Ting, both in terms of being—you know—how to do the science, but also how to lead a project?
I don’t think I learned from Sam Ting how to lead a project, because I don’t think there’s anybody else who leads projects like that.
I certainly noticed the incredible attention to a “cause” when Sam Ting wants to achieve something, and the fact that you have to really focus. So I knew that to achieve something, I had to focus. I was never able to focus as much as Sam Ting, but at least knew that this was a required part. I never had plans to achieve as much as he did, but I knew that if I want to achieve something, I had to focus which is difficult. I worked very long hours. It didn’t work well for my family life, and such things.
But certainly this type of focus and dedication, this was something which I learned. Also, the other thing which I learned from him and from his group is that, to get physics results, your equipment has to work, and has to work well, and one has to make sure that everything works well, and it is ready on time. This was very important. And the other thing which is very important is that I learned to work in collaborations. For me, the teamwork unbelievably important. I try to value people for their contributions.
I think that I can handle all kinds of people because I’m always trying to find something good about them and try to get as much contribution from them as possible. And this is something which you could see in Sam Ting’s group a lot. I mean, he had the people who were delivering were and they were very protected by him, and respected.
There are many people in his group who worked with him during all their professional lives because they had certain skills, certain abilities they would bring to the team. I think that this is something that is very important. He was very supportive of his people. And as you know, I owe him a lot.
And now that we have—
So I’m trying to implement it as much as I can and—
—you know, and I’m far from—
—his efficiency, but I’m certainly on track.
It’s a high standard indeed.
A high standard, yeah.
And now that we have the benefit of hindsight, Bolek, you can reflect on—you know, looking back, how realistic was it in terms of thinking about your tenure considerations to switch fields, and set up this new endeavor? How did that work out?
Oh, it was completely unrealistic. As I said before, the critical moment was that at some point, I decided I’m not going to get tenure. I had this idea of collecting points. So if I do not get the tenure, then I have to get a job somewhere else. So why don’t I just do certain things which then could be useful in the future? So I tried to do as many things as I could, which—you know—which are useful for the future.
I became very active, and I would take as many responsibilities as I could, and it was very motivating. And, again, I was very lucky that I chose this particular project. For example, I was doing two things. I was taking data at CERN, which was the small experiment. And at the same time I worked on the PHOBOS experiment at RHIC. And PHOBOS was advancing.
PHOBOS was facing very serious technical difficulties that I did not fully understand at that time. It could not happen the way we were planning it. It would have been a disaster. However, because of my project at CERN, I started to talk to people at CERN, other people, about similar detectors. In addition, in the WA98 experiment the silicon drift detectors, which we needed to look for our disoriented chiral condensate, were failing.
To get the WA98 measurement we ended up building another silicon detector on extremely short timescale. And we used it as R&D for the RHIC experiment, using different technology. We did it as a part of an incredible collaboration with Taiwan. The detector ended up to be very successful. But [laugh] one of the important elements of this project was a lunch in CERN cafeteria.
There were many things that happened to me in CERN cafeteria, a long list of important events. One of them was a lunch with one of my graduate student colleagues, Sam Ting’s student Yuan Hann Chang, who is a professor in Taiwan.
I was preoccupied with the fact that my detector wasn’t working, and I had an idea of building another type of silicon detector. I made a little sketch what I would like to have. But it really looked daunting, you know. You have to find money, set up a project, etc., etc. I had that sketch in my back pocket. We started talking, and my Hann introduces me to his colleague, Willis. And Willis says that he is working on silicon detectors, he would like to get some Taiwanese company to build silicon detectors. And I said, “Oh, by the way, I would like to build a silicon detector.” I pulled out the sketch from my back pocket, I showed it to him, and I explained the general features. Its size and application. He looked at me and said that they can do it for me. I asked if they need any funding but he said that they have the money. All I had to do is to provide a drawing of what I wanted. It took few months and lots of work for it to became a real detector. But they delivered. We then used some electronics from CERN, we adjusted its parameters. I built a lot of it myself, with my own hands. The final detector worked like a charm.
We had this working silicon detector and we used to make measurements of charged to neutral pion fluctuations. While working on this little detector we realised that, in principle, you could use the same technology for the PHOBOS detector at Brookhaven National Laboratory. We also realised that maybe it would be easier to do it this way rather than the way we wanted to do it originally. So here I am, in my position of a project manager. I now know how to build working silicon detectors because I just built one, and we have this big project that is not going well, with lots of people responsible, how do we change? How do we get out of it? This was a very complicated process.
The issue was: how do you convince large fraction of the collaboration, and the funding agency, to completely dump pretty much everything that they’ve been doing for the last five years, and bring this new stuff from CERN, and from Taiwan, and to rebuild it? It took a lot of time. It made a lot of people unhappy. Some people left the collaboration. Some people left the job. We brought new people in, etc.
I consider this my probably most important decision in my career that we changed the detector technology and related electronics. Of course, I didn’t decide it all by myself. As usual, I consulted. I had people coming into my office and argue both ways. I really thought very carefully, and I decided that we really need to change it.
And why, Bolek? Why was this so significant, this decision?
Because we had to deliver a working detector. Remember, physics results need a working detector, this is how you do things. And what we originally planned just didn’t work—the design and construction process was too slow, too expensive, too risky. And at CERN we had something that was working. We had to change the way of thinking about data taking. We had several individuals in the PHOBOS team who understood what needs to be done, what does it mean, how to change it, etc.
And it was a big rehash. We had to explain and justify everything, there was a DOE approval process, reviews, etc. We had to show up at a review and say, “You know, whatever we’ve done so far we plan to throw away, and bring in this new idea.” And two or three years later, RHIC accelerator starts. There are four experiments that have silicon detectors. Four collision points taking data at the same time, and only one of them worked. Only one of them actually worked.
Silicon detectors in other experiments worked just a little bit, but they were not fully ready. On top of that, our detector was 100% made of silicon detectors. If our silicon detectors wouldn’t have worked, we would have been dead. And not only it was working, but it was working fantastically, produced the very first physics result from RHIC accelerator. Professionally, this was really a great thing. And this is again an example that to get physics results, you must build well-working detectors. Those two things come together.
You don’t choose your detector technology because it is cute or it uses some cute techniques. Detectors have to work, and they have to produce results, and only then it matters. And this is what I definitely learned from Ulrich Becker and Sam Ting and others in their group.
I was a very intense project manager. I was running, day-to-day, night-to-night operations, very hands-on, very involved. It was really incredibly good experience for me. And the results were very interesting. Even though PHOBOS was a limited capacity detector, not a general purpose detector, it did many measurements of charged multiplicity distributions, that are very important quantities to measure in heavy-ion physics.
They you how the quark-gluon plasma gets made. Interestingly, one of the first things which we measured is—our very first measurement was a big surprise. It turned out that the total multiplicity is much smaller than what people expected, maybe by factors two, three, four. And this had very important physics implications, especially together with other measurements that became available at that time.
The main purpose of heavy-ion field is to measure something called quark-gluon plasma. If you increase the energy where quarks and gluons are produced, they eventually start approaching asymptotic freedom, where the forces between quarks and gluons become weak. This was a critical discovery made by Frank Wilczek that made QCD a real working theory. And when heavy-ion physics started, when people worked on increasing accelerator energies, etc., there was an expectation and a hope that in those higher energy collisions, for example, at RHIC, or maybe even in fixed target experiments, the quarks and gluons really become free. They start traveling long distances.
One of the implications, one possible implication, was that the multiplicity would suddenly increase dramatically. A cloud of weakly interacting particles. And to our surprise, the multiplicity was actually small. So something was unexpected. Then another experiment called STAR made measurements of asymmetric collisions, and they saw a very strong signal of so-called flow. And very quickly people realized is that the plasma which is produced at RHIC was not actually this soft asymptotic freedom plasma of quarks and gluons, but rather like a liquid, like a strongly interacting liquid.
In fact, those quarks and gluons, even at those very high energies, at very high energy densities, they do interact very strongly, and the whole collision behaves more like a bubble or a droplet of hot liquid, which is expanding relativistically. And a theory called relativistic hydrodynamics describes the properties of those collisions extremely well. The parameters which are adjusted in the model to describe have very extreme and very theoretically interesting values. We saw low multiplicity, we saw strong flow. Also at that time at RHIC, we started to produce jets. Jets turned out to be very suppressed.
Imagine that you have a collision of two blobs of two large nuclei. Somewhere inside you have a hard collision, so you produce a pair of very energetic partons. And normally those two partons would appear in the detector as jets with balanced energies—same energy on the left and right. But because of the presence of this hot liquid, on average, one of those jets was suppressed compared to the other. So you have imbalance of energy because some of the energy was deposited into the medium.
Those type of effects started to be seen at RHIC. We put it all together, looked at the particle distributions, and this in turn resulted in a change of concept of the quark gluon plasma. What we’re producing was a very strongly interacting liquid, which started new way of looking at it theoretically. It was very interesting.
After building PHOBOS detector, after getting the first results, with its very low multiplicity, it was time to go back to MIT. I used up my sabbaticals and my research leaves. I had to go back. Bob Jaffe, whom you’ve interviewed at some point, was in charge of assigning teaching: I got a double load of teaching.
Bob Jaffe, yes, seemed like a punishment for having discovered quark-gluon plasma.
[laugh] Welcome back.
Welcome back. So I’m back, and I am teaching like crazy, which was actually pretty good because I had to focus on one thing. The PHOBOS physics was done by my younger colleagues, everything was working fine and I was teaching.
One day, I walk in the corridor, and there’s a colleague of mine working on high-energy physics on CMS experiment at LHC, Paris Sphicas, and he tells me, “Look, we have this heavy-ion program in CMS. Why don’t you look into that?” And so I look into it. They wrote a very nice document on how to use CMS as a heavy-ion detector. There was a group of people in CMS suggesting this.
And how well-developed was CMS in heavy ion at this point?
It was surprisingly well-developed. There were several people in CMS who were very interested in all kinds of physics. This is not obvious, because, you know, different areas of physics can be very territorial. High-energy people don’t talk to heavy-ion people and vice-versa. But there are some people who are really interested in all aspects of physics.
One of them was Daniel Denegri, who was very excited about everything. He, together with a group of people, mostly from France and from Russia to look at what would it take to use CMS as a heavy-ion detector. They did a couple of analyses, a couple of examples, which were very much in line of what RHIC was observing. They looked at jets. They looked at shapes of events. But there was one critical assumption in this document that made the program a bit weak.
As I was reading the document I found that they are struggling with the following problem. The LHC heavy ion detectors were designed for particle multiplicity, which is extremely high. We compare particle multiplicity in terms of a number of charged particles per unit rapidity. Detectors at LHC were designed for 8,000 particles per unit rapidity. And to do that, you had to really jump through lots of hoops to make sure that the detector can measure all those particles.
And CMS could not possibly handle that. CMS could not handle 8,000 particles per unit rapidity. But, I just came from RHIC. We just measured the multiplicity. The multiplicity was surprisingly low. In PHOBOS, we measured 550 or so particles per unit rapidity.
The energy at RHIC is lower so we had to extrapolate it to LHC. We realized that we will get maybe 2,000 or 3,000 but not 8,000. What happens when you have a lower multiplicity? I started to talk to one guy in the United States who was working with CMS, Pablo Yepes. He was a tracking expert at Rice University. And he told me, “Look, I know tracking, and CMS can measure those tracks, no problem, with lower multiplicities,”. This is not an issue. The heavy ion team at CMS, wanted to switch off the tracker because they thought it will be useless, and to use only other sub-detectors to measure particles.
We realized that we don’t have to switch the tracker off because multiplicity will be lower. We started to work on the physics program and in 2002 we wrote a proposal to the Department of Energy. The proposal got rejected, and we were sent home to do some studies. So we did more studies, and, we ended up working for several years. Our proposal was being rejected on a regular basis, 2002, ’03, ’04, ’05. They finally gave us some funding in 2008. And every year, we would improve the physics case, and the prospects looked better and better.
At the same time, the RHIC physics was developing, and it looked more and more relevant for the CMS project. So by the time we got to the start of data-taking, in 2010, we were in pretty good shape, both in understanding what we want to measure, and detector preparation, etc. This was a lot of work that went into preparing this program. And there were all kinds of twists and turns during the process. Psychologically it was very difficult because we got rejected every year, we would be criticized at conferences etc.
But I was absolutely convinced. I had an intuition that we just don’t know how good CMS is. We just did not appreciate at all how good it was. There were a couple of features of the experiment that turned out to be critical and very helpful in using the detector designed for Higgs search for heavy ions.
I was absolutely convinced but I couldn’t fully measure it or prove it. But I was sure that it is going to work. It’s going to work better than we even thought at that time. And as we were moving on through those studies, things just got better and better and better. For example—
Bolek, what was the source of your intuition, right? Why did you feel like this was as promising as it would turn out to be?
Because I knew that they had very good detectors.
And what does that mean? What is a very good detector in this context?
For example, the most important detector for our program was the tracker. In CMS, the original tracker design included silicon detectors as well as some gas detectors, descendants of the wire chamber. Then they switched to silicon only and improved things a lot. We had our silicon detector at RHIC, we had experience working in this very high-density environment with lots of tracks. And we knew how such detector will behave. Also, we had some people in our team who were very good in tracking.
They understood very well how the tracking works. And when they looked at the silicon detector for CMS, they knew that they can use the same tricks, learned at RHIC to improve the performance of CMS. So, originally, the people who were working on CMS did not appreciate fully the techniques that can be applied to data from silicon detectors to make them work better. So I knew that it can be done better than what the studies are showing right now, and that we have people who can actually make it work better.
We spent a lot of time within the MIT group on the tracking and improving of the CMS tracker performance. One of our group members, Christof Roland, spent all his professional life doing incredibly creative things with tracking and silicon detectors. And every few months, he would improve things. And every time, the performance was getting better and better and better. And in the end, the tracker turned out to be an absolutely critical detector. Because of this tracker, we could reconstruct heavy-ion events with extremely good accuracy.
We could match tracks to other sub-detectors in CMS. We can do physics which is incredible. Also, the CMS data acquisition system was very innovative in that it was very flexible, one could reconfigure it for heavy ions data taking. There were all these bits and pieces which we were modifying to get CMS to work well for heavy ions. And as our proposals were being denied, we’ve been improving, improving, improving.
One thing that I had to figure out is how do I handle this psychologically? And it was very simple. I explained to myself that I’m from MIT, I have tenure, it is a cool project and I just will push ahead.
I would go to a review at a meeting, and I thought to myself, “Ooh, what can you do?” [laugh] How can you stop me? I was so convinced that I was on the right track with this project.
And how well did that play out? I mean, tenure considerations aside, just in terms of the science, how well did that play out, both in the short term and the long term?
You mean the CMS heavy-ion?
Yeah, it has been—it was absolutely stunning success. There were couple of results. First of all, the very first results from the MIT heavy-ion group actually came not from heavy ions but from proton-proton physics. One of the important considerations when we do heavy-ion physics is that the predictions of exactly what happens in a detector are difficult to make. It’s difficult to simulate heavy-ion collisions because they are complicated—it’s a collisions of large objects. We make measurements, but the predictions are not extremely precise.
So you want to compare it to something simple, for example, to proton-proton collisions. When we collide two ions, for example lead ions, it is like colliding two bags of 208 protons and neutrons. One can compare it to let’s say 1,000 proton-proton collisions. Depending on what you want to do, you can combine a certain number of proton-proton collisions and look for differences with heavy ion collision. Proton-proton is a reference for heavy-ion collisions.
Also, proton-ion collisions are also a good reference. You do not expect quark-gluon plasma to be formed in those collisions. So LHC starts taking data with protons. And there was a postdoc at MIT, Wei Li, who suggested that we try to look for proton-proton collisions that have very high multiplicity. Multiplicity is an indication of something interesting is happening.
And a typical proton-proton multiplicity may be around six, seven charged particles on average, something like that, depending on energy. Wei Li suggested to look at proton-proton collisions at 100 or 200 or maybe 300 particles. Those collisions are extremely rare. So how do you find them? How do you select? Well, you have CMS.
CMS has an extremely powerful data-acquisition and triggering system. We have so much CPU power that you can just throw those measured collisions at this enormous computer farm, and you can have an algorithm that counts particles in real time, and that selects only those very high-multiplicity collisions. There was no other detector in the world that could do it. The postdoc was working at MIT. He couldn’t go to CERN because of visa restrictions.
He wrote an algorithm that can select those high-multiplicity events. We took the data. We collected this unique sample of high-multiplicity events. He started to looking at the data—basically repeating techniques that he used for his PhD thesis with the PHOBOS experiment. He was measuring correlations of particles. And he saw very clear heavy-ion-like features in the data, which were not explained by any proton-proton simulations and such. This was the first indication that the quark-gluon-plasma-like effects occur in high-multiplicity proton-proton collisions.
He then went on and discovered similar phenomena in proton-nucleus collisions. We found that something, which we thought is exclusive to the heavy-ion collisions, starts occurring in more elementary collisions, if the multiplicities are higher. This was very unexpected. To make such measurement, you just had to have this general-purpose, enormous machinery that could be retuned for these unusual measurements, and of course you had to have somebody who knows it, and who can actually use it.
It is similar to taking a Ferrari to go shopping, I think. It is a simple measurement in principle, but you need a Ferrari to really be able to easily extract the information. This is what CMS brought to the table. And then there were other measurements like, for example, measurement of Upsilon states. CMS is optimized for muon measurements and it can do very high precision measurements. As a result, CMS is the only experiment at LHC that can disentangle the three states of Upsilon, and measure them separately. We measured all three and there was enormous suppression of higher Upsilon states. This was always considered as an important indication of quark-gluon plasma. We could measure it very cleanly. It was just incredible.
There is a heavy-ion physics conference that takes place every about year and a half. It is called Quark Matter, and it is the most important conference in the field. The first conference with first results from LHC was in Annecy near Geneva. And because I was the leader of this project for the previous 10 years, I was given the privilege of presenting the summary of all first results from CMS heavy ions to the whole community. People brought me all those results, the different CMS sub-groups making measurements. I presented something that looked like a Christmas tree full of gifts. We can measure this. We can measure that, etc. At the end of my talk I announced that: “CMS can measure anything.” [laugh] People really laughed at me.
I was really excited. After all those years where people would tell me that we cannot measure this or that because were not designed for heavy ion physics. But it turned out that we had basic working machinery. It was designed very well to measure particles and it was very large. In particular, sub-detectors had many channels, so we could recognize all elements of heavy ion collisions.
In addition, and probably most importantly, our group had lots of young people who were just very, very smart. MIT is a place that constantly gets a flow of fantastic young people. It’s year after year after year, you have fantastic young people who come in, and those young people work with people from other institutions who are also excited, so they also are fantastic. And we formed this great team of young people who were producing those real cool results. I always felt that my job is just to make sure that they get what they need for their work.
Bolek, I’d like at this point if you could reflect a little more broadly, you know, about the scientific process, and how you understand this remarkable transformation from the doubting and the naysayers among your colleagues and peers to this remarkably successful and ongoing research project. How did we get from point A to point B? What do you understand as, you know, some of the valuable lessons that are not only specific to this particular narrative but the bigger takeaways in terms of how to go about setting up a successful scientific collaboration like this?
I think the first and most important thing are the people—the people who have vision who are interested, who have a good education, who can think well. And for the skepticism, I think it is just part of life that there are some people who are dreamers and there are people who are conservative. I think a healthy mix of those is important.
When I think of those years from 2002 to 2008, I know that we have improved our project dramatically during that time. This were the many years of incredible skepticism. And of course it was not just skepticism. There were people who were enthusiastic.
But this was a period of time when, you know, a healthy dose of skepticism forces you to do better and to improve and to work harder and so on. So I think it was we were so much better prepared in 2008 than in 2002. You know, if somebody would fund our original proposal back in 2002, probably it would not have been as successful. So I think every project has to go through a period of skepticism.
It was long time. It was heavy on me personally. But at the end, the project and the program was much better because of that, I think. During reviews, when I am getting criticized, it is always very hard for me personally. But, so far, I was never stopped because of a bad review or negative review. I always tried to look at them as a way to improve.
In case of CMS, this was certainly what happened. In case of reviews of PHOBOS at RHIC the reviewers were not tough enough. They did not find what was the real problem, so we had to find it ourselves. But in CMS, I think we did better because of good reviews. You need to have visionaries, people who really want to do something for whatever reason, but also you need to skeptics to balance the process.
And can you talk, Bolek, about some of the long-term theoretical implications of what CMS has uncovered so far?
CMS has done very, very solid experimental work on multiple aspects of heavy-ion collisions. We now know exactly how many particles are produced, where do they go, what are the momenta. Many jet phenomena were measured with high statistic, with high precision. We measured Upsilons, heavy flavor mesons etc etc. There is a lot of good solid data available. And with this good solid data, you can then develop theoretical models for what happens. And many of the theoretical models—initial, original theoretical models—that were thought to describe that is going on in heavy ion collisions became obsolete. On the other hand, the general properties of the collisions were described very well by relativistic hydrodynamics of a strongly interacting liquid. But simultaneously, somewhat by coincidence, some of the theoretical ideas on how to explain strongly interacting matter, strongly interacting fields, and so on, they were developed in the context of gravity. Many techniques used to explain heavy-ion events were based on the gravity-based superstring theories. I never fully understood details of how it works.
Heavy ion collisions produce strongly interacting matter which is much, much more viscous than a typical water or a liquid. And CMS and other LHC experiments provided a very precise picture of what’s going on experimentally, such that one can really try to get a much better understanding of what is going on. You can distinguish for example that if the quarks and gluons bounce from each other in hard collisions, if they radiate very low-energy gluons, quarks or photons or higher energy partons? Is it some sort of bulk phenomenon or is it a local phenomenon? Lots of details like that can be extracted from our data.
We have this detailed information from CMS. I don’t think we’ve made a major discovery, I think RHIC was much more revolutionary in terms of new physics, because RHIC was the first heavy ion collider that very significantly increased the collision energy But RHIC detectors were much, much less powerful and precise than LHC detectors. The combination of the two really advanced the heavy ion physics.
And, Bolek, at what point did you—of course, CMS is ongoing—but at what point did you sort of step back and take on new projects?
I haven’t stopped working on CMS. I work on CMS. Being the LNS director slowed me down somewhat.
For which? For both?
We finished PHOBOS at RHIC experiment in 2005, so no more activities there. Our MIT research group moved 100% into LHC in 2005. And I was working on CMS since 2002 for almost 20 years.
And then when did LHC start?
LHC started taking data in 2010. In 2010, I was in sabbatical at Ecole Polytechnique near Paris but I was at CERN and near CMS most of the time. And since becoming the Laboratory director, I slowed down somewhat. Right now, I am working on starting a new hardware project for the next phase of CMS. And this hardware project will bring a completely new feature to CMS, which will expand our physics reach.
So let’s get to LHC. Talk a little bit about how you became involved on a sustained basis in 2010.
Well, I became involved in sustained basis in 2002, 2003. This is when I started to go to CERN frequently to work on CMS heavy ion program. CERN for me is my mother lab so it was natural.
Right, all the way back to when you were a kid, essentially.
Exactly. I could never separate myself. When I switched to heavy-ion physics, I started to work at Brookhaven, and it took me about three years to go back to CERN. [laugh] So I never could disconnect from CERN, I am constantly involved in CERN-related things. I feel very much at home. I know exactly what needs to be done when I work there.
I spent many, many years in Geneva area, so I know my way around. I plan to stay involved with CERN as much as I can. I missed my summer stay at CERN first time in many, many years this summer because of COVID. I would go every summer to CERN, and spend time there.
Coming back to CERN after the RHIC/Brookhaven experience had an additional interesting challenge. There was another issue with heavy-ion program at CMS, which was highly nontrivial. The problem was that most of the CMS collaborators did not appreciate heavy-ion program very much. I mentioned earlier that physicists are quite territorial with their physics fields. Many high-energy people in CMS did not want to waste time on taking data on heavy ions. They thought that this is some sort of niche thing. Why should they worry about it?
My job was also to improve the standing of the heavy-ion physics within CMS. And I benefited from a very interesting twist of fate again. It turns out that about one-third or more of CMS membership were people from L3, my LEP experiment. This was the experiment where I was a postdoc. And I knew many of the leaders and senior people in CMS from my time as a postdoc. Many of them were very skeptical about the heavy-ion program.
They of course remembered me from the time when I was a reasonable postdoc doing their kind of physics. And they gave me benefit of the doubt. They allowed me to share my excitement of heavy-ion physics and they trusted me since they knew me from the past. It’s human—simple human relation. I was not an enemy. I was a friend.
They allowed me to talk. And I overcame a lot of skepticism by this type of, you know, personal connections, etc. They were very skeptical of the field of heavy ions. Towards the end of 2010 the data came in, we had to turn on CMS for heavy ions anyway because this is what the accelerator was colliding. Our team, the heavy ion group within CMS, started to produce results, and those results were very nice and very recognizable. We spent a lot of time advocating and explaining. And very soon this became a very high-visibility physics program within CMS.
I plan to continue to work on CMS because there is still a lot of potential, with upgrades to equipment, with increased intensities and different types of ions. There is quite a bit of physics you can extract.
Calling CERN your mother lab, of course, has an emotional connection. But, of course, there’s also a scientific connection. I wonder, you know, given all of your experience in laboratory environments in the United States, what is so compelling to you about just the way that science happens at CERN?
I also spent time at Brookhaven, and I think Brookhaven is a fantastic laboratory. It has great people. But it is different.
CERN is where I started. This is where I feel most comfortable. I was involved in multiple projects over the years. Partially it just happened that way, that there were projects which I was interested and which were available at CERN, etc. But it just easier for me to work there.
I know my way around quite well. I know the system. I know how all works. I know how to do things at CERN. And I really like very much the international aspect of CERN. I really like how open it is, and I always enjoy the diversity of people who are there.
I was at CERN during Balkan Wars, Indian-Pakistani conflict, Cold War ending, the formation of EU. All kinds of important worldwide events were happening while I was at CERN. For example, during Balkan Wars if you wanted to hear the Serbian story, you just went down the corridor and talked to a Serbian. If you wanted to hear the Croat story, you just went on the other side of the corridor, and talked to a Croatian. And if you wanted to talk about Indian-Pakistani War, you could sit with a couple who were Indian-Pakistani, and they will tell you their story and how they feel about it. I found it very fascinating.
There were Russians at CERN. There were Iranians. People from all over the world coming and working together, and being, you know, very reasonable and very nice and friendly and collaborative, etc. So it was—it’s a really unique place.
CERN has pretty strict rules about being nonpolitical which helps. Once, when Pope John-Paul II, the Polish Pope, came to CERN, we, the Polish community, wanted to put up some flags and do a little political display. We were told that we were not supposed to do it.
I enjoy working with teams, collaborations. At CERN it is easy to have a diverse group of people, and people of different cultures have a different attitude to work, and a different attitude to solving problems. We used to joke that for example there is a Catholic approach to science, and there is a Protestant approach to science, and [laugh] we would laugh, and try to find out, if we can really see it, working with different people. For example, and I’m joking here a bit, I always enjoy having a Dutch person on the team because Dutch seem to be always questioning, and they often ask the most difficult questions.
They are more stubborn. And if you want to have a successful team, you have to have somebody who’s very stubborn—
—and always says, “No.”
And it just happened that in many teams I was in, there was some Dutch person who was playing this role. Having a good knowledge about different culture helps tremendously. So I always try to find out as much as I can about people’s culture, where do they come from, and how they react, etc.
Bolek, of course, the CMS research and the research at CERN were quite different in many ways. But I wonder for you what might’ve been some of the connecting points in terms of your broader interests, the kinds of questions that you were asking that may have been relevant for both endeavors?
You see, I am very curious about, how things work, and so I always try to find the fundamental principles. I am a particle physicist. we like to smash things apart, and look what is inside, what are the mechanisms, etc. Being at MIT as a member of MIT’s physics department is very fortunate because I have access to all kinds of things that physicists are excited about. As the laboratory director, I have to read proposals and listen about ideas of people who try to pursue different measurements and do different things. And I find it just absolutely fascinating to learn about what other people doing.
One question that really caught my attention few years ago was the question about the origin of heavy elements. How do you make uranium? How do you make gold? t turns out that we know more or less how they are made. They are formed in a chain of nuclear reactions, so-called r-process. But it turns out it’s not obvious where these reactions occur. The most obvious place would be in exploding supernovas but apparently they do not produce enough, the numbers don’t exactly match. There was a possibility that maybe most of those elements instead come from collisions of neutron stars.
Anna Frebel from MIT Physics department who is an expert in very old stars and she studies element formation, discovered a small galaxy where many stars were made at exactly the same time, and there was so much material containing heavy elements that it must have been produced in a collision of neutron stars. Then fast-forward a couple of years, LIGO experiment observes neutron star collisions, and in its afterglow one could see traces of large quantities of heavy elements.
But Anna and other astronomers need information about the nuclear physics to figure out the details of element formation. During conversations with them I realized that we don’t have anyone working on the low-energy nuclear physics at our laboratory. And that there’s a lot of interesting things that can be done by studying the nuclei.
And so I started working on expanding this area of studies at our Laboratory at MIT. We wrote strategic plans, we organized the faculty search and lo and behold we hired a new junior faculty working on the low-energy nuclear physics. He will benefit from the opening of the new accelerator at Michigan State University. And guess where we find the person? We found him at CERN.
I’m in a position where I can actually move things a little bit here and there. And our footprint at CERN expanded even more. We are covering many areas: heavy-ion physics, high-energy physics, low-energy nuclear physics. And of course Sam Ting and his AMS team is at CERN as well. Somehow I cannot get away from CERN—
—it seems. It’s just getting more and more.
Bolek, how did your directorship for the Laboratory of Nuclear Science come about?
We—you know, it’s a rotating position. So there are people who have to help other people running the show. There is a long list of people who did it in the past.
What’s the average tenure for a director?
It is maybe six years, nine years, sometimes a little less, a little more. It’s a cycle of three years, so it’s two or three cycles.
And did you see this as sort of a—I don’t want to say an obligation. But was this sort of a service opportunity for you to give back to MIT?
I like to do such things, I like to help other people organize things, and have projects, and do things. So, for me, this was a pretty natural thing. My predecessor decided, after nine years, that it is time to do other things. So he asked me if I am interested and I said yes.
Later there was a selection process, and the Dean of Science Mike Sipser chose me, so I’ve been doing that. Something that came later is the directorship of Bates Laboratory. Bates is a place where we can build detectors for experimental projects. It is a pretty unique and valuable place for MIT. We can do more than at the typical university. And we can do things quickly. We have plenty of space. We have quite a bit of freedom to do things. It was a little complicated how I became Bates director while being the LNS director. But it turned out to be quite natural.
During my time as the Bates director we managed to survive a very detailed DOE review, which ended up pretty favorably for us. So far, I’ve managed to keep things going pretty well. Of course, there’s still a lot of work to make it even better. Naturally, I’m trying very hard to bring a CERN project to the Bates lab, obviously. We already have projects at multiple national labs in the US. I like to do such things.
And then your other directorship at Bates in 2018, how did that come about?
This is a little complicated MIT internal issue. It was very natural for me, let’s put it this way. But so let me not go into detail of how it came about. But that it was both practical reason and, because I was interested.
There were two separate directors LNS and for Bates for historical reasons. When Bates was a large linear accelerator user facility, it obviously made sense to have a separate director. There were hundreds of users coming and working there. It was large and separate laboratory. Ernie Moniz was one of the directors of Bates, at the time when this was a large lab.
After shutting down the accelerator operations, the lab became much smaller, but it kept the same administrative structure, with a separate director. But it was less and less obvious that you need to have two separate directors, it seemed to make sense for just one director managing both labs, especially if the LNS director was spending already a lot of time at Bates. At some point people from Bates came to me and asked for me to become also their director. But the actual formal decision of merging the two positions has not been made. So I have two titles.
Bolek, in what way has your directorship in both places been useful for your own research that precedes and is ongoing these responsibilities?
CMS is ongoing. Bates is a very important part of that experiment because it is hosting a large computer farm mostly for CMS. We need to keep the computer farm going happily at Bates.
And also being a director, it have some extra discretionary funds, that I can use to pay for my travel. I used to travel a lot before COVID, so being a director helped a lot. Also, it’s a quite visible position and it gives me the opportunity to talk to the funding agencies etc.
I have to advance the interest of the laboratory in various places. And of course, once I am meeting agency representatives then I can also discuss my own projects. It’s helpful.
And, Bolek, just to bring the narrative up to the present, what are some of the projects that you’re working on, you know, now and for the past few years?
At this moment, I would really like to start a hardware project, part of a collaboration which is already ongoing, which is to add a new detector to measure particle flight time. In CMS physics program we do not have the ability to distinguish between different types of hadrons. It is very helpful in heavy-ion physics, to distinguish pions, kaons and protons at relatively low energies. You can then look at more details of the relativistic hydrodynamic expansion of the hot bubbles.
Another experiment at LHC called ALICE can do particle identification very well. But ALICE acceptance is relatively small. They look only at a fraction of event. CMS wants to build a timing detector that will have very large acceptance. If we can do particle identification in a very wide range we could then compare different regions of collisions which would be very, very helpful.
This project is moving ahead, and we would like very much to participate. I would like Bates Laboratory to build the mechanical structure of the detector. Wheels about three meter in diameter, five centimeters thick, holding tens of thousands of detectors together. The engineers at Bates can build it, and it would be a nice contribution to the experiment. This detector will expand the physics potential tremendously.
It is still quite some time away, but part of the CERN’s success is that they plan things very well and very much in advance. We are still in pretty early stages. Being at MIT, working at Bates we need to make sure that this is done, and then we will need to have a team of people who would get physics out of it in 2027 and beyond. Yeah, so it’s a long term.
I can imagine it’s probably safe to assume that, at some point, CERN will beckon again for you.
Yeah, that’s the plan.
What kind of work do you envision yourself doing there in the future?
I don’t know exactly. These days to extract data from an experiment, you have to be a very good computer programmer, at the end of the day. Some time ago, I realized that my graduate students are so much faster than me.
I just could not keep up, etc. This is a little bit of an issue for me. How can I contribute directly? But somehow, when I go to CERN, there’s always something useful I can do.
By the way, since we are talking about technical contributions. I have a hobby: I write database programs mostly to do various administrative procedures. I do things which nobody else really wants to do, but I like it. I sit by myself in my room doing little coding. And I have been actually quite successful in delivering several of those projects. For example, in CMS, back in 2008, we were about to start the heavy-ion program. And I was doing everything possible to know as many people, to, socialize the heavy-ion program.
At that time I was asked to be in charge of assigning speakers to talks at various conferences I was supposed to be a chair of the CMS conference committee. My first reaction was that this is crazy. It sounded like a horrible job. Why would I want to do it? But then I realized that to do it I will have to meet a lot of people.
I agreed. I knew that this is a pretty large database problem. There are 3,000 people in the CMS collaboration, there are 200 conferences each year, each conference has several talks. So for each talk you have to find one person, one of 3,000, give them the talk, make sure it’s recorded, approved etc. Often you have to decide between several candidates. It would be a pretty complicated database program, but I did such things in the past. I decided to take this job, and I wrote a database system to handle that.
The system went into operation in 2008, and it is still running, and I’m the only programmer for the whole thing, and it has been a wild success [laugh]. The thing runs. There is no manual. It just runs.
By now, I think, we have about 25,000 talks in there at 1000 conferences, and it’s just working. In fact, all LHC experiments are using this system for the talks which are shared between them and CMS. There are about 15,000 people using this system. Cool.
From time to time I introduce some new options here and there, or improve things. I use it as a distraction from other things. It is just one of my database projects. As my contribution to educational activities in the physics department—I, together with a colleague, wrote a database to keep track of all students in the department. We have about 5,000 students and alumni with all their grades and exam records in the system.
At some point I wrote a gradebook for MIT. We used to keep track of grades through Excel spreadsheets. About 20 years ago I wrote a little program on the web that was easier to use. MIT copied it, and up to very recently, they were using it for all the students. Who knew? And this is something which has nothing to do with my research.
The conferencing system, on the other hand, really increased my visibility inside the CMS collaboration. Everyone knew who Bolek is, and at least for the two or three years, when I was in charge of the conference committee, they had to listen to me [laugh]. I used this to advertise the heavy ion program. So this little hobby of mine actually gave me tremendous visibility, and helped in advancing my research program. Every time I travel to CERN, I spend some time upgrading my system since it is easier to be inside the network firewall.
[laugh] Well, Bolek, for the last part of our talk, I’d like to ask you a broadly retrospective question, and then we’ll look a little more toward the future. So, looking back, to go back to what you said about technology, given that your career spends—spans a time when computers were not nearly as central to the research as they are now, so much so that, you know, generationally, you’re starting to see the differences between your own abilities and those of your graduate students.
Of course, yeah.
So I wonder if you can reflect broadly on what this means in terms of computational power, using your powers of extrapolation, you know, looking back, what this means for the future of experimentation, given how important increasing computational power will have?
There are two aspects of the computing power increases. So, number one, if there’s an important physics question that needs to be answered, then one should throw at it everything you have in your technological arsenal. Adding computing power is certainly a way to go. You just have to make sure that the data which is going into your computer is of good quality. I think everybody understands it. LHC physics is an example of exactly this type of thing.
High Energy physics certainly benefits from more computational techniques, computers are dramatically important for LHC. LHC now is upgrading. They’re improving their instrumentation to cope with much higher luminosity. Much higher luminosity means more collisions, more data, more selectivity, and so on. Amount of data from LHC will be increasing dramatically. And there are improvements to computation techniques and algorithms.
This is really cutting-edge. At LNS, we have people who are working on such improvements because advances in computing are so important for the type of physics which we do. Maybe you’ve heard, but we just received a large NSF award to host the Institute for Artificial Intelligence in Fundamental Interactions at LNS.
This is just so natural to me. CMS experiment for example produces very good quality data. But you really need new algorithms to be able to extract it. As an example, the measurement of Higgs decaying into bb ?, this measurement was published maybe last year, by LHC experiments. Just a few years ago, in textbooks of particle physics, this was an example of Higgs decay with a relatively large cross-section, but at the same time impossible to measure because one was not able to distinguish b jets from other jets. It turns out that physicists figured out the way. They used sophisticated machine-learning algorithms to really focus on very slight, differences between b jets and other jets. This measurement was possible only because of advancement of new techniques.
Such new algorithms are absolutely critical to the progress. One of the important goals of the new AI institute at LNS is to fully understand how reliable are those fancy algorithms, what is the uncertainty in the measurement. If you discover events that look like the events from your theory, you still need to estimate how well do you know it. How precise is the measurement? Advances in computing go absolutely hand-in-hand with this.
However, there is a danger. Our main purpose at MIT is to educate young people. And there is a disconnect between the timetables for large experiments like CMS, how long it takes to build something new, how long it takes to build a new piece of equipment, and the data analysis when you extract the data, and so on. We have students who spent almost all of their training time in front of a computer terminal, without ever seeing experiment, without ever having, for example, Ulrich Becker coming and asking you to build things [laugh].
Which is problematic. It’s not ideal.
Which is not ideal. But students know it. Students know it, and you see students coming into the lab and choosing smaller research groups. CMS is a very large collaboration. But at LNS we have also quite a few extremely exciting, smaller groups, smaller teams, which are working on improvements of detectors, making crystals to look for neutrinoless double beta decays, dark matter, neutrino mass. There are many detectors that are being designed and built where students can learn a lot about instrumentation. So there are possibilities. The problem is that it is difficult to do both large experiments and direct experimental work. But even that is possible but managing is tricky and it’s difficult.
Well, Bolek, for my last question, you know, obviously it’s hard to predict, as you already indicated, exactly what you’re going to work on in the future. But I want to zoom out a little, and ask not specifically what you personally are going to work on, but what are the new frontiers in your research areas that you’re personally excited about, the kinds of experiments that you can conceive, you know, will be as fundamental if not even more so than all that you’ve been involved with up to this point in your career?
In particle and nuclear physics, there’re always some unanswered questions. Some of these questions become “fashionable” at various moments of time. Presently the fashion is to find out the properties of dark matter. There are many efforts in different directions trying to discover particles constituting dark matter, the dark matter searches.
This is a very difficult area because you just don’t know what you’re looking for but you know that you’re looking for extraordinarily small signals. So it’s difficult to fine-tune your detector to look for a specific signal. Several people in our lab, who are very good in developing experimental techniques, are working on that. This is an example of an area which needs a breakthrough at some point soon, hopefully, because that’s a very important question.
There are also new facilities being built. When you build some new facility which is really significantly different than anything that was before, for example when RHIC started to operate, it usually leads to major changes in the related physics. There could be revolutionary changes because you can do things which you couldn’t do before. Another example is physics that came out of CMS, which was a detector which was much more powerful than anything that was done before.
When you look around at the new facilities the Michigan State Facility for Rare Isotopes is something worth watching. It is such a dramatic change in capabilities in terms of availability of rare isotopes, and it comes so timely in respect to developments in astrophysics. So I expect that they will be able to really make very significant measurements.
Something that I was not aware until relatively recently, is that one can use these rare isotopes for measurements of fundamental quantities like electron dipole moment and many others. I think this is a very interesting new era—new facility that will produce lots of interesting results. I’m very happy that LNS is now moving into that direction.
There are new results from LIGO, for example, observing collisions of neutron stars that we can use to get more information about how neutron stars are built, the domain of nuclear physics. A combination of new experiments, new facilities will bring answers to important questions in nuclear and particle physics. Some of those questions are very old.
And, of course, neutrinos. I think there are some people in the lab who actually can make a real difference in understanding neutrinos, possibly discover neutrino mass, and make the first measurements neutrinoless double beta decays. It’s not excluded. In general better understanding of neutrinos is always good. There are lots of exciting projects that are coming up.
There’s no shortage?
There is no shortage. And then, of course, there are other fields of physics, for example condensed-matter physics, which is just exploding with results here at MIT. So I find myself incredibly fortunate to be able to zoom from one topic to another.
[laugh] Well, Bolek, on that note, I’m so happy that we connected through our mutual friend, Sam Ting. And it’s been a real pleasure speaking with you today, and gaining your perspective on all of these, you know, unique and important research endeavors that you’ve been involved with, and the quite compelling, you know, origin in terms of your own start in physics, and how this all came about for you, which has been instructive and tremendously interesting. So thank you so much for spending this time with me.
I really appreciate you took time. Now, one thing which Sam Ting mentioned to me that sometimes you may want to have, you know, other people who might be interviewed. So if I can put my candidate for you, and that is Professor Wit Busza.
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