Oral History Transcript — Dr. Gerson Goldhaber
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Interview with Dr. Gerson Goldhaber
Gerson Goldhaber; February 27, 2006
ABSTRACT: Gerson Goldhaber (1924- ). Early training at Hebrew University in Jerusalem (1942-1947). Graduate work at The University of Wisconsin. Research at Columbia University (1950-1953); memories of Rabi. Research at The University of California at Berkeley and at Lawrence Berkeley Laboratory (LBL). Took part in first experiment at Bevatron. Worked on K-mesons, the tau and theta mesons; measured the radius of interaction, and the difference between the behavior of like and unlike pion pairs; contributed to the design effort of SPEAR (Stanford Positron-Electron Asymmetric Ring) accelerator at SLAC; co-discovered, and named the Psi particle with George Trilling; Goldhaber found the naked-charm mesons; with colleagues, measured the lifetimes of a number of particles, including the tau lepton, the D mesons, and the B meson; at SLC (Stanford Linear Collider) did measurements of the mass and width of the Z particle, measuring how much of the Z decay went into neutral leptons. With colleague Robert Cahn, he wrote and published the textbook ďThe Experimental Foundations of Particle Physics.Ē Part of The Supernova Cosmology Project (SCP) since 1989. 2004, ĎGersonfestí held in his honor.
TranscriptSession I | Session II | Session III | Session IV | Session V | Session VI
First, we go over the rough draft of the paper written by Ursula Pavlish about Professor Goldhaber.
Goldhaber:Alright. So, I picked one title. The others are too pretentious. I have added something to it: From the Antiproton to Charmed Mesons and on to Dark Energy. Thatíll be fine. Most of it is fine. Thereís one place where we discuss the antiproton which needs to be corrected. There are some corrections there. Also, I donít like superlatives. ďMonumental career.Ē Everywhere, wherever you have things like that, think about it. Here I just have a clarification. This is in connection with the experiment I did with Lederman. The experiment involved exposing emulsions soaked in water inside the cyclotron to get at high energy positive pions. Two energy points, okay. Then, this is unnecessary. You donít have your computer with you? I sent you an emailÖ
Pavlish:About the antiproton. I got the email but I didnít get the attachment.
Goldhaber:It didnít come along? Okay. Well, maybe we have to print it out here. Itís a talk I gave. We just had an antiproton symposium. What I wanted to clarify is, at the beginning we decided that we needed to expose at high energy. Thatís not the energy of the Bevatron; itís the energy of the antiproton beam that was taken out of the Bevatron. Those antiprotons were too energetic to stop in the emulsion. So what we did is we put a five inch copper piece in front. That caused a lot of trouble. First of all it caused the trouble that there was lots of background in the emulsion. Secondly, the antiprotons have a large cross section. You mention that Teller pointed out that antiprotons have a larger cross section. That killed most of the antiprotons. So we just ended up with one event in that stack. And thatís the one that was found in Rome. Now, that one did not have energy large enough to show proof of annihilation. When I say energy, I mean visible energy, what was emitted visibly. So then we had a second exposure where we lowered the energy of the antiproton beam. Again, you say the Bevatron. I changed that. Then we were able to stop the antiprotons in the emulsion. And also we cleaned it out. In that second exposure, thatís when my colleague Gosta Ekspong worked with me. There, we immediately found the antiprotons. If we had done this to begin with, we would have seen it long before the counter experiment. The thing I sent you is my talk at this yearís conference. If you canít get it then I will try to print it out here. Thatís the main point. Just the order is different. Itís the second antiproton star, which really proved the annihilation. When I say proved, you see what SegrŤ, Chamberlain and company did was to show there is a particle of negative charge and of mass close to the proton mass and also a production consistent with antiproton production, but they could not show annihilation. My experiment was the final proof that there were really antiprotons. They went ahead and published it anyway saying, ďWe found the antiprotonĒ but they hadnít proved it. The final proof was in my paper. Thatís the point I want to make. That deals with this here. You try and decipher it, see if you can and if not, we can discuss it. This is all about the antiproton. Here I say, ďas well as several other groups at the Radiation Lab.Ē It wasnít just me. In general, I include saying ďour groupĒ rather than saying that I did everything. Okay, I think those are most of the comments. There was something else at the beginning. This tau and theta business was important. I have here, ďfollowing the study of the tau meson by Dalitz, it was realized that the tau and theta mesons had different parity. This led Lee and Yang to propose that parity may not be valid in weak interactions.Ē In other words we showed that they had the same mass and the same lifetime and Dalitz showed that they had different parity. The solution was that parity is not conserved in the weak interaction. That was a very important result at the time. If you canít read something, we can discuss it tomorrow. Now, where do you want to publish this? Do you want to publish this?
Pavlish:I think that your idea of publishing the interviews along with your papers that you gave to me, and pictures, photographs, maybe some of your art, is a wonderful idea.
Goldhaber:Well, thatís longer range. Thatís not going to happen in the next week or two.
Pavlish:This paper will be revised before I submit it. If you like it well enough then perhaps it could figure in that collection. Perhaps someone else could write a better paper. Then this could be a supplement, like a research write up.
Goldhaber:Did you manage to do any work at the university this year?
Pavlish:No. I have been given leave, so Iíll be going back in the fall.
Goldhaber:Youíre doing okay now?
Pavlish:Yes, thank you.
Goldhaber:Good. So this is something that youíd publish in a History of Science magazine or submit to a professor or what?
Pavlish:I asked Peter Galison first, if these discoveries could be called scientific revolutions by Thomas Kuhnís definition of the term, so it was kind of a technical question. Then, I asked him if he knew of a good history of the Bevatron. Heís in France right now but he wrote to me and said, ďOh, Iíd be very interested to read your paper.Ē So, if it would be okay with you, when itís more developed I might send it to him.
Goldhaber:I know him well.
Pavlish:He said that he knows your nephew as well.
Goldhaber:My nephew and my great nephew and my brother. Yes. I guess, when youíre done with it. I donít know how people write these papers in the History of Science but it seems to me that you have too many quotes from other people.
Pavlish:Thatís something I need to work on.
Goldhaber:But maybe thatís how you write these papers in History of Science.
Pavlish:I plan to have some people look at it for comments.
Goldhaber:My main comment is leave out the superlatives. Iím a scientist and thatís fine. Otherwise when youíve made these corrections, Iíll read it again. If you want to submit it to Galison, thatís fine with me. Alright, so what did you want to ask? Let me give this to you, and maybe when you have a new version I will read it.
Pavlish:My first question is, in a previous interview you said that you were born in Chemnitz, Germany and that you lived there until you were nine years old if I am correct. Do you have any memories of that town?
Goldhaber:Yes. I remember the school I went to. In fact, about three years ago I was invited to give a talk in Berlin and in Dresden and I took that occasion to make a quick visit to Chemnitz. I visited for half a day and I saw my school. Our house no longer stood there. They built another house in its plot. I saw the spot but it wasnít our house anymore. I donít know the history of that when it was destroyed or what. Then I saw the school where my brothers and sister went. I also went to the Jewish cemetery and I found the graves of my grandparents. They lived there and I was pleasantly surprised that their graves had not been destroyed, that it was well kept and theyíre still there. They died after I left Germany. They were living in Chemnitz at that time and died of old age a few years after we left. Now there was a whole thing about a statue of Maurice, of my brother. While we were still in Germany, while he was at the gymnasium, they chose eight students to make statues of them and put them in front of the school, in front of the gymnasium. But then we had heard that during the Nazi period, there were two Jews among those eight statues, and they were removed. Later on, I gather, they commissioned new statues and put them back. Anyway, I went to see this place and there are indeed eight statues. I couldnít tell whether my brother was among them or not. Anyway, that was a small amusing thing about Chemnitz.
Pavlish:Do you remember what the landscape is like? Do you remember walking down the streets there?
Goldhaber:Yes. We had a villa and a large property around it and I had lots of friends. All of the neighborhood kids were friendly and we played in our place. Yes, I remember walking to school. School was about a quarter of a mile away from our house.
Pavlish:Did you walk to school with your brother or did you go by yourself?
Goldhaber:My brothers and my sister were much older than me. I came twelve years later than they. They went to the gymnasium already when I went to first grade.
Pavlish:Do you know how your family settled in Chemnitz?
Pavlish:Do you know where your parents or your grandparents came from?
Goldhaber:Yes. My parents came from Poland and my father as a young man left home and traveled around the world and ended up in Egypt. He got very interested in Egyptology and worked in the tourist business there. This was in around 1905 when Einstein published his papers. Then, he went back home to get married and then spent some time there. My three siblings were actually born in Lemberg, in Poland. It was Austria at the time. Just before the First World War, they all returned to Egypt. He liked the place. As it turned out, it kept him out of the First World War. However, it did catch up with him. The British were in Egypt so he was then considered an enemy alien. He was interned during the First World War for several years. That had a lot to do with his leaving Germany so quickly. He didnít want that to happen again. He knew that they were beginning to intern Jews or at least arrest them and so on. During the First World War, the British placed women and children on the boats with the idea that it would stop the Germans from sinking them. I donít think it had any effect like that. So my mother and my three siblings were sent back to Poland during the war, while my father stayed in Egypt in internment. After the war was over, he was released. He went back to join his family there. At that point they went to Germany. Then, within a year or two I was born.
Pavlish:Then your grandparents also came over?
Goldhaber:Then my grandparents also came to live in Chemnitz.
Pavlish:You didnít have other relatives there then?
Goldhaber:Yes, we did. My father went there partly because his brother and family lived there. Also, my mother had a brother and sister living there. So yes, we had some family there. Unfortunately all of those who stayed behind got killed by the Nazis. It was several families with children. They all perished.
Goldhaber:What was your question again?
Pavlish:That was my question: how did they settle there, where were your parents and grandparents from?
Goldhaber:We left Germany. It was one day I was at school. The teacher said, ďOh I have something to show you,Ē to the class. What he had to show us was that they had rounded up some Jews and had them clean off the election posters from the wall. You know the walls were covered with posters. They had them wash off the walls. I recognized some people that we knew. When I came home, I told this to my father and he left immediately, that same day, for Berlin where my two brothers were studying at that time at the university. He got visas for all of us to Egypt, so this is how we got to go to Egypt. He left for Egypt right away, he and my oldest brother, and then my mother sold off our furniture and she and I followed. My brother Maurice and my sister Friedel left for England shortly thereafter.
Pavlish:What were your father and mother like? What were their occupations? What were their personality characteristics?
Goldhaber:Thatís hard to say. They were very nice and easygoing people. Not the Germanic types. I couldnít describe that. My father was very interested in Egyptology. He was very outgoing. He gave a lot of talks on Egyptology. He never got a university degree, but he had a practical knowledge of Egyptology. My mother was interested in the family and took care of the family.
Pavlish:What were you like as a little boy?
Goldhaber:You already have a description there. I liked to build things.
Pavlish:You liked school?
Goldhaber:I tolerated school.
Pavlish:Last time you mentioned that you had some notebooks in which you wrote down experiments that you did as a boy?
Goldhaber:Thatís true. I havenít found them yet. Iíll take another look.
Pavlish:I thought that even that might be really fun, if you do put the book together, to have a page from one of your notebooks.
Goldhaber:The notebook only has a few pages. I have a picture, I got some prizes in school for the things I built. I have a picture in one of those books I got, of the apparatus I built to measure g. I forget the details of it now but maybe Iíll remember when I see the picture. In general, I always had things going on in my room. Building things, and so forth. In that sense, my mother was very tolerant.
Pavlish:Are there any letters or other documents that might be relevant in putting together a wholesome picture of your youth?
Goldhaber:Possibly. I have to think about that. Not offhand.
Pavlish:This relates to your building of things. Did you have a natural propensity for physics as a boy? Do you remember what it was like when the material was first introduced to you? Did the subject seem counterintuitive at all? To some people, the first introduction to physics seems that way. Or did the material just seem to come naturally?
Goldhaber:It came naturally. I enjoyed it. When I was a student at university, I spent a month doing the Millikan experiment because I liked it. I always liked the experiments which were done in physics courses. I built a Tesla coil and I found some effect which involved some attraction. I couldnít reproduce it now. But anyway, I discussed it with my professor at the university. He said, ďInteresting.Ē This was while I was a student at university. The other stuff was while I was in high school. I built various things.
Pavlish:What period, high school, graduate school, your time at Columbia or at Berkeley made you the physicist that you are today? What would you say were the most influential years of your life?
Goldhaber:Itís hard to say. They were all influential. Perhaps mostly when I came here to Berkeley and really started working on serious experiments in particle physics. At Columbia I was already doing particle physics. Actually, I was doing particle physics also as a student in Wisconsin. But I kept increasing the energy as we went along. Thatís happened ever since.
Pavlish:Back to your move to Cairo, what was it like for you as a boy? Was it strange, exciting, and disorienting?
Goldhaber:It was exciting. First of all, I didnít know any of the languages. I started out at the French school but I didnít stay there very long. There were only private schools that I could go to. The French was expensive. I donít know how we decided that I should learn English. I didnít know French and I didnít know English. So then I went to an English school and thatís where I graduated.
Pavlish:So you had to learn English quite quickly?
Goldhaber:Yes. I had to learn English. I learned English and I also took French. In principle, I had to take Arabic. I managed to convince them that was too much for me to do, to learn three languages at the same time. I know Arabic but I only know spoken Arabic. I donít know the written Arabic, which I would have learned had I taken those classes. I talked them out of it.
Pavlish:Were your classmates friendly?
Goldhaber:Oh yes, very friendly. They were a very nice group of people, a very mixed group.
Pavlish:Was it an international group?
Goldhaber:International, yes. I learned to curse in at least four languages.
Pavlish:This goes even further back, if you can remember, what is your very first memory?
Goldhaber:Yes, I do remember that. I think I was about three. We went on a trip to Helgoland. I remember the boats; they had these paddleboats. I remember these paddleboats turning. I think thatís pretty much my first clear memory.
Pavlish:What is Helgoland?
Goldhaber:Helgoland is an island off the German coast, which is a vacation place. I donít know what itís called in English.
Pavlish:You went there with your family? Do you remember being there with your family?
Goldhaber:Yes, I remember mainly this. From pictures and so on, I remember the family. But thatís more hazy. You asked for the first, there can only be one first.
Pavlish:How about your first memory relating to physics?
Goldhaber:Well, that was what we discussed that I did chemistry experiments. The first one was what you described, making hydrogen with a friend of mine, an older friend. I was nine or ten, and I had a friend who may have been twelve or thirteen. We tried it in our bathtub, to produce hydrogen by submerging burning coal, and it worked.
Pavlish:I was wondering, do you have letters from when your brother Maurice was in Cambridge and you corresponded with him? Did you keep those letters?
Goldhaber:Maybe. Iím not sure. I keep everything but this may not have survived all the travel.
Pavlish:You mentioned last time that you and your brother were separated for about seventeen years when you moved to Cairo, Egypt, and he to England. I was wondering, were there other long separations in your life? What did your parents do after you left for the Hebrew University and later for the US?
Goldhaber:They followed us within a year or so. They came to the US. In fact they stayed with us in Wisconsin and later on at Columbia. They came to the US maybe a year after I came. In particular, they stayed in Wisconsin, they stayed with Sula while she finished her PhD when I had gone to New York. Then they followed us to Berkeley. They came to Berkeley.
Pavlish:Thatís wonderful. Did you like that?
Pavlish:It was an extra support.
Goldhaber:Yes. Off and on they lived with us occasionally. They rented an apartment here in Berkeley.
Pavlish:My next question is, where have you traveled? Has physics taken you to exotic places?
Goldhaber:Yes. The most exotic was when we started on a trip around the world. I had a sabbatical; we were going to make a trip around the world. We went first to New York, and then we went to a conference in Oxford. Then we took some time in the Greek islands. Then we went to Israel to visit my sister and Sulaís brother who lived in Israel. Then we went on to India. Thatís where Sula died. Then of course we cut short the trip and went back home. Our son was with us. He was about seventeen then. It was a tough trip. The ending was tough. Before that, we enjoyed it.
Pavlish:This question is changing gears again now. I was wondering what your relationship to computers has been since they evolved while you were working.
Goldhaber:I started working with computers as soon as that became possible. Iíll always remember when I had to study an emulsion event; it took me a whole day with a slide rule to calculate the details of this particular event. It was a great relief once we got computers and calculators. Even the calculator was a big advance over the slide rule.
Pavlish:What exactly is a slide rule?
Goldhaber:Itís a calculating device. I have one here. I have sort of an exhibit of various items. This is a slide rule. Itís a logarithmic scale which allows you to multiply numbers. Youíre lucky that you donít know what a slide rule is. I built this device to do some calculations. In photographic emulsions we had say, three tracks. The question is, are they in a plane? You have all the angles, you have also the dip angle, this can be adjusted here.
Pavlish:What is this called?
Goldhaber:I donít know.
Pavlish:You came up with this?
Goldhaber:Itís my device. Itís to determine whether three tracks are in a plane. You put in the length of the tracks, you put in the dip angle, and the azimuthal angles of the tracks, and if this ends up in a plane when you have put in all these quantities then the event is in a plane. If the three are like this, then you donít get a plane.
Pavlish:How do you compare that to the emulsion?
Goldhaber:What you measure in an emulsion is a length downwards and you measure the distance here and you set this up, and reproduce it here. It wasnít precise but it was a quick and dirty way. That was before computers. This is a slide rule I built to measure nuclear reactions when I was doing nuclear physics to calculate how much energy is released in a nuclear reaction.
Pavlish:May I look at that?
Pavlish:This is also before computers? What did you do?
Goldhaber:Whatís given here is the energy. I have to tell you, I donít remember exactly how it works. You shoot in a deuteron and out comes a proton, or you shoot in a neutron and out comes an alpha particle. These are all interactions and then you calculate the energy. You start with some nucleus, say Nitrogen 13, and you figure out where it ends up. This allows you to calculate how much energy is released. So that was a slide rule I built. This is how I used to do computing. In early computing you had to plug in wires to get the connections for the computer. Then I have punch cards. You wrote a program and you had to punch it out in cards and you had to wait till the next day to see whether you mispunched something and had to do it again.
Pavlish:Around what time was this, when you used punch cards for computing? Do you remember what decade?
Goldhaber:It was about the 1970s.
Pavlish:If you could divide your career into epochs or periods how would you do that? I did it a certain way in the paper and I was wondering if you would do it that way or differently. Iím going to turn the tape over so it doesnít run out.
Goldhaber:The first divisions are obvious. I studied at school in Cairo (1934-1940), then I studied at the Hebrew University for a masterís degree (1941-1947), then I studied at Wisconsin for a PhD (1948-1950). Then I went to Columbia for three years (1950-1953) and then I came here in 1953. Those divisions are easy. Coming to Berkeley, I would divide it up by the type of experiments that I did. From 1953 when I started here to 1958 or so I worked with photographic emulsions. Then I switched over to bubble chambers. In 1959 we published this paper, which established that pions follow Bose Einstein statistics. Then I worked with bubble chambers until about 1972.
Pavlish:You were the expert.
Goldhaber:There were other emulsion groups, I should say, in Berkeley. I was the one in SegrŤís group. Then, after that in 1973 we joined up with Burt Richter and company until 1989, a slight overlap there to 1990, to work at SLAC.
Pavlish:With electronic detectors.
Goldhaber:With an electronic detector. We went through three different accelerators. The SPEAR was the first one, which gave us the psi and all that. That was the most simple and the most successful one. Then we went to PEP where we measured lifetimes of states and importantly the B meson lifetime. George Trilling was particularly active in that work. Then we went to the SLAC linear collider and studied the Z particle. The shortest period was at SPEAR and the most exciting was at SPEAR because we discovered this whole new form of matter which led to a clear understanding of the quarks.
Pavlish:You werenít thinking about quarks before the psi discovery, right?
Goldhaber:There were experiments already before, in fact at SLAC also, the electron scattering which indicated that there was something hard inside the proton. That was around 1968 or so.
Pavlish:You were familiar with these experiments?
Goldhaber:Somewhat. I realized that this was happening. But then we just decided that we go in this new regime and leave the bubble chambers. By the way, the 72 inch bubble chamber which Alvarez and company built was rebuilt into an 82 inch and went to SLAC. We did an experiment with that bubble chamber. That was before, around 1970 or so. Thatís where we discovered the anti-Omega minus.
Pavlish:So you were already at SLAC then?
Goldhaber:We did the experiment there and we analyzed it here in Berkeley. Yes, 1970-1971 we discovered the anti-Omega minus. This was me. This was the event. It got a lot of coverage all over the world.
Pavlish:This is all material related to that?
Goldhaber:Yes. The Wall Street Journal. This is the event. Hereís what it looked like. It was a 12 GeV K plus interacting with a deuteron. It produced an anti-lambda which then decayed into an antiproton and a pi plus. This is the particle; see this little stump here. Then it produced a lambda, this is a lambda, pi minus, proton. The main thing is, this has strangeness plus three. The Omega minus has strangeness minus three. This has strangeness plus three. This was the one exciting thing. Then hereís this one over there, the anti-Omega minus. We have a paper on it. I can probably dig up one of those for you if you want. This is one of the exciting results, which came out of our work.
Pavlish:This is a whole article about it. Here it has, ďGoldhaber explained, the new discovery is significant primarily because it completes the evidence that antiparticles exist for all the semi stable baryons. While there was little doubt in physicists minds that the particle should exist.Ē So it was predicted already?
Goldhaber:Yes. Once the Omega-minus was predicted and later discovered, then you also predicted that there should be the antiparticle for it. Every baryon has an antibaryon. This was the last one. We knew that it exists but we didnít know we were going to find one. We found just a single one in our experiment.
Pavlish:Would you call that a golden event?
Goldhaber:Yes. Letís see, he was a student, he was a postdoc, Alex Firestone, and these two were scanners who helped find it. [insert picture]
Pavlish:You said it was a K and a deuteron that come in. Did you choose those particles?
Goldhaber:Yes. We were doing an experiment, K plus on deuterons, to see what happens. Hereís the reaction. If you want to see some of these, maybe we can make copies.
Pavlish:Would that be difficult to make copies or do you think I could take it home tonight and bring it back tomorrow?
Goldhaber:Sure. You can do that. I have here lots of letters. People congratulating me.
Pavlish:If I remember, you didnít even mention this particle last time.
Goldhaber:No. Then we had a party on the occasion. This is Wonyong Lee. Yes, you can borrow this. I trust you.
Pavlish:Iíll take it home tonight and bring it back tomorrow.
Goldhaber:So that was one of the things we did with SLAC. I told you about some of our discoveries, I didnít tell you about all of our discoveries.
Pavlish:So we have more to talk about this time around.
Goldhaber:Whatís your next question?
Pavlish:You told me last time that you did a masterís thesis on X-ray crystallography and a PhD thesis on the photodisintegration of the deuteron, building what you called ďthe worldís most cumbersome gamma ray spectrometer.Ē How long were these dissertations? How much work did they take, were they arduous to write? Were you working all the time or did you find that you had time to just relax?
Goldhaber:I never worked too hard. The one written in Jerusalem was arduous because it was written in Hebrew and my Hebrew wasnít that hot. I spent the first year at university learning Hebrew. I knew it a little bit from my Bar Mitzvah but I did not really know Hebrew. I had to learn Hebrew and finally I had to write this dissertation in Hebrew. This is it.
Pavlish:Did you draw those diagrams?
Goldhaber:Possibly. Somebody did. Anyhow, so that was hard. Writing papers, I always find a chore. I like to do the work. Iím less keen on writing it up, though I realize thatís important.
Pavlish:Did you learn a lot in your thesis work or do you feel like you learned more later on, as you went along in your career, when you were already in the workforce. Can you quantify that, how much you learned?
Goldhaber:Yes, I certainly learned a lot about X-ray crystallography that I didnít know before.
Pavlish:If you were to describe X-ray crystallography to a lay person how would you do that? Have you ever tried?
Goldhaber:No, I havenít tried. Itís beyond description. You have to mount the crystal and expose it to an X-ray beam. It was a complicated camera, a Weissenberg camera. It made an exposure by, you both rotated the crystal and moved the film. I donít remember in detail how it works because Iíve never done any more X-ray work after that.
Pavlish:Was your work in your masterís thesis helpful at all for your PhD thesis?
Goldhaber:Yes. It got me to know how one works in a laboratory and how one builds things and so on. Yes.
Pavlish:Did you find that as you switched from project to project, I had a question here about what was your transition like between projects. But even further than that, how much carried between your work in your masterís thesis to your PhD to Columbia to Berkeley and so on?
Goldhaber:Very little. You have to learn new things. When you change techniques, you have to learn new things which are largely unrelated to the earlier things.
Pavlish:But there wasnít a very steep learning curve, or if there was, it wasnít steep for you.
Goldhaber:Not too difficult.
Pavlish:How can you tell when youíre on the right track with a problem, which youíre on to a discovery?
Goldhaber:Usually you see it. You look at the data. You have a graph or this, what I just showed you the anti-Omega minus. You reconstruct this event and there it is, you see it. The same is true when I found charmed mesons. You have those papers. I just saw a peak in the distribution. The main thing where experience helps you, is to know when itís significant and when itís not. Thatís very important. You canít go and claim something whenever you see a little fluctuation. You have to realize when it is a significant effect. At least in the things Iíve been doing, that was always fairly clear.
Pavlish:Thomas Kuhn says that a lot of science is like doing puzzles. I was just wondering if you ever thought of the work you were doing in that way or if you would characterize it differently.
Goldhaber:I never quite thought of it that way. The type of work Iíve been doing is to look at the data and see what happens. Itís sometimes called a fishing expedition. Much of my work has been along these lines. Although some of the work like looking for charmed mesons, I deliberately looked where the theory predicted them. But in other cases, I just looked. With the antiproton, again, I was looking for something specific. The Alvarez group was doing negative K mesons in a bubble chamber and they found wonderful results. They found all these resonances. In particular, the K minus and a baryon, a proton, give all kinds of particles. I said, ďWell, if you can do it with K minuses then why not with K pluses?Ē So, to be different, I studied K pluses. I tried and tried and tried and never saw a resonance, a K plus proton resonance. The reason was the quark model. A proton consists of three quarks, two up and one down. But a K plus consists of an up quark and an anti-strange quark. The K minus consists of a strange quark and a down quark. With the strange quark you can produce Baryons with strangeness. But with an anti-strange quark you cannot. You have to have a five quark system to produce a positive strangeness baryon. Some people have recently claimed evidence for such a ďpenta quarkĒ system. But this is rather doubtful.
Pavlish:Youíd have to have one more particle. You couldnít just have a K plus and a proton.
Goldhaber:Yes. So this was the basis for the Omega minus, that itís a decuplet. Maybe this is going too far. I drew this picture for Yuval Neíeman for his eightieth birthday. I indicated all the various particles. When I showed that there is no positive strangeness baryon, then this was the solution that you had to have an Omega minus. Here he is putting an Omega minus on top of this pyramid of ten particles.
Pavlish:Is that a poem accompanying it?
Pavlish:Next to it, it says, ďThe Gap Was Worth One HundredÖĒ
Goldhaber:Yes. He sent me a poem, so I sent him this picture. Thatís the gap that I discovered. This gap, that thereís no positive strangeness baryon.
Pavlish:I still donít understand exactly how it is a gap. What does that mean?
Goldhaber:It doesnít exist. This particular thing doesnít exist.
Pavlish:When you have a K plus and a proton, the fact that you donít have a resonance is the gap?
Goldhaber:Yes, that there is no K plus proton resonance. Essentially, yes. Until then, when you had something with a negative particle, youíd get a corresponding situation with a positive particle. Here it didnít work. They just called it a gap. Gell-Mann and Neíeman called it a gap. I donít know if you can read it from here.
Pavlish:ďEven before the Standard Modelís days/ While formless spectra lingered on the desk/ Yet none in the particle table so picturesque/ Fermi made the beams/ They searched throughout that maze/ Pions scattering off nucleon targets in several ways/ But one day the theorists saw Fermi, Romanesque/ Stare unbelieving at an arabesque/ He had seen where that peak, the Delta lay/ A kaon beam off that nucleon scattered/ Thatís the way to have a peak of our own/ Thought Gerson, as itís been shown/ Yet there was no peak/ A failure that mattered/ Then said Yuval and Murray, ďWeíll put you on the map.Ē ďBehold, this is the Goldhaber Gap.Ē
Goldhaber:They wrote that in their book. Not the poem. They coined this phrase.
Pavlish:In what book?
Goldhaber:Thereís a book by Gell-Mann and Neíeman. Thereís just one book by Gell Mann and Neíeman. There they coined that phrase.
Pavlish:Is this picture of yours published anywhere? Itís a really cool picture.
Goldhaber:No. I just did it last year.
Pavlish:I see there on the poem it also says, 28 October 2005.
Goldhaber:Yes, and I did that afterwards and sent it to him. This is a Xerox copy.
Pavlish:Thatís maybe a good closing point for today.
Thatís fine with me.Session I | Session II | Session III | Session IV | Session V | Session VI