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Leon Lederman (1922–2018)

10 October 2018

Colleagues of the Nobel laureate remember his passion, intelligence, and stories.

Leon Lederman
Credit: AIP Emilio Segrè Visual Archives

Editor’s note: This post was updated on 5 November with a new submission.

Particle physicist and science education innovator Leon Lederman died on 3 October in Rexburg, Idaho, at age 96.

Born on 15 July 1922 in New York City, Lederman studied chemistry at the City College of New York and, after a stint in the US Army during World War II, received a PhD in particle physics from Columbia University in 1951. A parade of major discoveries followed, including the long-lived neutral K meson in 1956, the muon neutrino in 1962, the first antinucleus in 1965, and the bottom quark in 1977. He shared the 1988 Nobel Prize in Physics with Melvin Schwartz and Jack Steinberger for the neutrino work, which demonstrated that the particles come in more than one flavor.

In 1978 Lederman began what would be more than a decadelong stint as director of Fermi National Accelerator Laboratory in Batavia, Illinois. Along with supporting researchers and their work at Fermilab, he also became active in science education policy. He worked with Stephanie Marshall (see her submission below), the Illinois state government, and others to found the Illinois Mathematics and Science Academy in 1985. He also advocated the teaching of “physics first,” before biology and chemistry, in high-school curricula; he explained why in a 2001 Physics Today commentary that drew plenty of supporting and opposing feedback.

Rather than have one person write an obituary, we asked some of Lederman’s colleagues to share remembrances. Their responses are below. If you would like to share a story about Lederman, please send us an email or leave a comment.

  1. Rocky Kolb
  2. John Yoh
  3. Stephanie Marshall
  4. Thomas Ferbel
  5. Luigi di Lella
  6. Leslie Camilleri
  7. Bernard G. Pope
  8. Michael J. Tannenbaum
  9. Nari Mistry

Rocky Kolb
Dean of Physical Sciences, University of Chicago

It’s impossible to describe the many dimensions of Leon Lederman in just a few sentences. Scientist, teacher, educator, organizer, writer, science spokesperson, leader, director, visionary, mentor, friend—the list goes on. His impact was wide. Leon was equally comfortable speaking with third graders as with US senators. He could write for the Physical Review as well as the general public. He was equally at ease speaking to a national television audience and engaging the person in the airplane seat next to him.

Leon imagined new possibilities and empowered others to realize his vision. In 1983 he recruited Michael Turner and me to start a theoretical astrophysics group at Fermi National Accelerator Laboratory. His light management touch gave us free rein to explore the connection between inner space and outer space. Leon’s style was to regard science as an adventure—perhaps a serious adventure, but one that was a great deal of fun.

Leon imagined Fermilab as more than a physics laboratory. He viewed it as an international cultural institution. He entertained visiting artists, musicians, writers, politicians, and scientists in his Fermilab farmhouse. Over dinners he charmed those guests with a seemingly inexhaustible supply of jokes and stories. (I believe some of the stories may have even been true!)

The world seems a smaller place without Leon in it.

John Yoh
Scientist Emeritus, Fermilab

Lederman and Yoh
Credit: Fermilab

Leon and I worked on three experiments. The most significant one was at Fermilab E288 (Columbia-Fermilab-Stony Brook), which in 1977 discovered the upsilons, the first particle of the bottom quark family. The third one was the CUSB (Columbia University–Stony Brook) experiment at the Cornell Electron Storage Ring—an experiment I originated with Steve Herb—which codiscovered upsilon 4S/5S, the basis of B factories. The earliest one where I met Leon was at CERN in an Intersecting Storage Rings (ISR) experiment that missed the charmonium (later named J and ψ, which Leon et al. saw the first hint of in Brookhaven in 1968) but discovered lead-glass darkening instead.

Working with such a genius was often frustrating for me, since
I could not match his insights. But that was compensated by his joie de vivre, his jokes, and his stories. I learned a lot from him, often at 2:00am in the E288 counting room, where this picture of us was taken. He had an enormous number of ideas, many of which were exceptionally prescient. I will miss him.

Stephanie Marshall
Founding President and President Emerita, Illinois Mathematics and Science Academy

Leon was a significant person and presence in my life, professionally and personally. We met in 1983. He was the director of Fermilab and I was the associate superintendent of curriculum and instruction for the Batavia school district. I visited him to introduce myself and to learn more about his Physics First initiative, with which I agreed. It was a simple premise: Don’t teach science alphabetically. You need “physics first” to understand biology and chemistry.

Two hours later, an idea was born. We discovered that although we were over two decades apart in age, we were both born in the Bronx in New York and had gone to one of the City Colleges as undergrads. We started talking about the Bronx High School of Science. He turned to me and said, almost off the cuff: “We need a Bronx High of Science in Illinois.” Not knowing what I was really saying and how it would change my life, I said, “Great, I’ll do it!”

Little did I know then that not only was Leon a renowned scientist and laboratory director, but also he was the governor’s science adviser. And so, after a tumultuous and fascinating period in Illinois political history, the Illinois Mathematics and Science Academy (IMSA) was established in 1985 through a remarkable partnership of scientists, educators, business leaders, legislators, and the governor. Leon was appointed to the new school’s board of trustees. I became founding president in 1986 and remained until 2007.

After retiring from Fermi, Leon moved into an office at IMSA as part of a new resident scientist program. He loved interacting with the students and staff, and the feeling was mutual. Watching him walk our building with his ice cream cone was a highlight for students. Stopping to talk to him was even better. He loved to engage them, to challenge them, to ask them questions, and then to really listen—and, of course, to share a silly joke.

Leon was a gifted scientist and teacher and also a wonderfully kind, generous, and wise mentor. In 2007, the year I stepped down as IMSA’s president, Leon and I delivered the commencement speech together. It was titled “Two Kids from the Bronx.”

I am grateful for the uncommon bond Leon and I shared, the ideas we brought to life together, the institution we and others created, and the students whose lives we were able to change. And I am grateful for the man: my partner, mentor, champion, and friend.

Thomas Ferbel
Professor of Physics, University of Rochester

I first met Leon when I was a graduate student at Yale in the early 1960s. My friend invited me to tea to see the great men and women at Columbia University, where he was a student of Gary Feinberg’s. He pointed me to Gary, Steven Weinberg, I. I. Rabi, Tsung-Dao Lee, the graduate student Juliet Lee, Jack Steinberger, Mel Schwartz, Chien-Shiung Wu, and Leon, among others. What a parade of stars!

Leon always seemed like a breath of fresh air. He had an extraordinary sense of humor, he was easily approachable, and he was fair. I recall dealing with him after our group had a run at Fermilab when he was director. We needed an extension to collect more data that seemed to contain a hint of a new process. When I approached him about that, he said that I should write him a single-page letter in longhand about what we wanted to achieve and he would get back to us. It didn’t take me long to respond, and Leon acted very rapidly to grant our extension. I thought it quite remarkable that he was willing to let us proceed just like that.

The last time I saw Leon was during his final visit to Fermilab, about five years ago, when I learned about his issues with dementia. As usual, he was outgoing and gave me a hug. Although I expected that he would not recognize me, he seemed to be pleased with seeing me again. He was a wonderful scientist and human being.

Luigi di Lella
Particle physicist, University of Pisa

I was at Columbia University as a visiting associate professor in the years 1969–70. Leon, who was at that time director of Nevis Laboratories, had just finished an experiment at the Brookhaven Alternating Gradient Synchrotron (AGS) to study the production of m+m pairs in proton–nucleon collisions. The experiment measured muon directions using scintillation-counter hodoscopes and muon energies by range in iron, so it had limited resolution on the dimuon invariant mass. However, it used the full AGS proton beam aiming at a thick uranium target, so it was sensitive to very small cross sections. Today we would call it a high-luminosity experiment.

The results from that experiment showed an unexpected production of dimuon pairs with a continuous mass distribution, which was soon interpreted as resulting from quark–antiquark annihilation via one-photon exchange. The dimuon mass distribution also showed a shoulder around 3 GeV, which was most likely due to the production of the yet-undiscovered J/ψ particle decaying to m+m. The J/ψ was simultaneously discovered in 1974 by Samuel Ting and collaborators at the AGS, and at the SPEAR e+e collider by  Burton Richter and collaborators.

At CERN, the first proton-proton collider ever built, the ISR, was due to start operation in 1971. So, while at Columbia, I joined Leon in writing a proposal to search for e+e pairs at the ISR. The proposed experiment had excellent resolution on the invariant mass of e+e pairs thanks to the use of total absorption electromagnetic calorimeters consisting of two large arrays of lead-glass Cherenkov counters.

Leon spent a lot of time at CERN in the years 1971–72 to prepare the detectors and to take data when the ISR was turned on. This experiment, known as R-103, discovered an unexpected high yield of neutral pions at high transverse momentum, which was several orders of magnitude larger than expected. This was an important result, but, unfortunately, there were also high-transverse momentum π0 pairs emitted at opposite azimuthal angles, which dominated the trigger rate in the search for e+e pairs. In the 1970s computers were still in their infancy, and data were being written onto magnetic tape at a rate which could not exceed 10 events/second, so the only way to keep the trigger rate below this value was to increase the trigger energy threshold. We ended up accepting only e+e pairs with invariant masses above 3.1 GeV, thus excluding the observation of the J/ψ particle.

Working with Leon was for me a privilege and a great pleasure. I remember him as a physicist with enormous imagination and a boundless source of stimulating and often unconventional new ideas, which he always presented in a friendly and joyful atmosphere. Obviously Leon loved physics, and his love for physics was contagious.

Leslie Camilleri
Columbia University and CERN (honorary)

When I came to Columbia as a graduate student in 1963, I had my heart set on having Leon Lederman as my thesis adviser. He was so well known that I had heard about him as an undergraduate at Imperial College in London and as a summer student at CERN. He took me on and put me on a muon–proton elastic scattering experiment that tested muon–electron universality.

Although Leon was involved in several experiments at the time, he followed our progress closely, from building the detector (optical spark chambers!) all the way to publications. He also ensured he had first-class postdocs to supervise us. But it was his enthusiasm for the physics and his sense of humor that made working for him so rewarding and fun. He loved pursuing new physics avenues and telling jokes, often self-deprecating. On one of his visits to our counting trailer at Brookhaven, he put a brown bag in the fridge. It was days later that we dared investigate: It contained a rubber chicken!

Following my thesis, I returned to England and then went to CERN for a fellowship that allowed me to chose the group I joined. The ISR was operational, and CERN, Columbia, and Rockefeller (CCR) were running an experiment searching for electron pairs and single electrons (see di Lella’s contribution above). Columbia was led by Leon, and I had no hesitation in joining CCR. Following this experiment, the three institutes proposed a far more ambitious one based on a superconducting solenoid and cylindrical drift chambers, a forerunner to modern collider experiments. Leon was one of the key physicists to push the concept. The readout electronics for the drift chambers was designed and built at Columbia’s Nevis lab. The experiment, which ran at a record luminosity of 4 x 1031 cm-2 s-1, observed Drell–Yan electron pairs, the upsilon, direct photons, and jets. Leon eventually left the experiment.

During my sabbatical stay at Fermilab in 2003, my wife and I joined Leon and his wife for dinner. I remember him telling us, and being rightly proud, that of his 51 graduate students, he still knew what 50 of them were doing. Leon’s disappearance is a loss to us all who had the opportunity to be associated with him.

Bernard G. Pope
Emeritus Professor of Physics, Michigan State University

I was a graduate student at Columbia from 1965 to 1971, initially working as a summer student on the muon-scattering experiment referred to above by Camilleri. Then I studied under Leon for my PhD on the dimuon experiment (see di Lella’s contribution above). This pioneering experiment discovered the large and unexpected production of dileptons from quark–antiquark annihilation and also saw the first hints of the J/ψ resonance.

The experiment was carried out at Brookhaven for a few months in the winter of 1968–69 with a group of only six people: Lederman, assistant professor Jim Christenson, postdoc Peter Limon, visiting professor Emilio Zavattini, and two graduate students, George Hicks and me. We monitored the experiment around the clock with 16-hour shifts each during a particularly snowy period on Long Island. Leon was extremely hard working, inspiring, and encouraging during a very exciting but difficult time.

Subsequent analysis of the experiment suggested further study at the CERN ISR, this time searching for electron pairs. I was pleased and proud in my position as CERN Fellow, and later staff member, to be working in the group of Zavattini and di Lella and to continue my association and friendship with Leon. At about this time, Leon and I wrote a paper relating the observed dimuon spectrum to the production of the intermediate boson via the conserved vector current hypothesis. Leon tried in vain to persuade Columbia theorist Norman Christ to be involved, since Leon wanted the authorship to be Christ, Pope, and Lederman. This is a typical example of Lederman’s humor. I am extremely proud to have studied and worked with such an exceptional scientist and warm human being.

Michael J. Tannenbaum
Senior Physicist, Brookhaven National Laboratory

I think that I first met Leon when I was a summer student at Columbia’s Nevis Cyclotron Laboratory in 1957. One of my jobs was chopping dry ice for his diffusion cloud chamber. I really started interacting strongly with Leon in the summer of 1960, when I was a summer student at Brookhaven National Laboratory (BNL). I spent lots of time reading about electron elastic and inelastic scattering and talking to Leon, who got me interested in a question: “Why does the muon weigh heavy—is there a force of mu-ness?” He told me about the muon scattering experiment that he was planning at the new Alternating Gradient Synchrotron (AGS) at BNL. I decided to go with Leon to do my thesis on muon–proton elastic scattering to compare the radius of the proton measured with muons to that measured by Robert Hofstadter and Dick Wilson with electrons, to deduce the difference in the radii of electrons and muons. We found there was no effect.

Although most of the equipment for my thesis was built at Nevis, I took up residence at BNL in the summer of 1961 to devote full time to setting up the mu–p experiment. BNL was far enough from Nevis that when Leon came to BNL, I got to work closely with him and sometimes have dinner with him when he stayed overnight. My most memorable recollection was a discussion at dinner by Leon and Val Fitch at the Brookhaven Center. Val had asked Leon’s opinion whether it was worthwhile to push the limit of the K20 → π+ + π branching ratio to below the value of 0.6% in Leon’s discovery experiment at the Cosmotron. I remember that Leon strongly emphasized to Val the importance of pushing the limit, because Bob Adair had generated excitement at BNL in the fall of 1962 with his group’s observation of anomalous regeneration of K01 mesons and his claim of a fifth force. Val’s (and James Cronin’s) experiment led to the discovery that the decay of K20 → π+ + π was an example of CP violation.

Ironically, my mu–p thesis experiment (shown in the photo) was located at a beam that was between the neutrino beam that got the Nobel Prize for the muon neutrino, and the neutral kaon beam that got the Nobel Prize for CP violation. Yet here in 2018, six years after the Higgs boson was discovered, I still don’t understand why the “muon weighs heavy.”

Tannenbaum with Lederman and colleagues
Left to right: John Tinlot, Rod Cool, Michael Tannenbaum (seated), and Leon Lederman in 1961. Credit: Tannenbaum

I have two other memorable Leon stories related to my thesis.  In addition to being a great teacher and collaborator, Leon saved me from flunking my departmental oral exam after I had submitted my PhD thesis. The committee was Lederman, I. I. Rabi, and Robert Serber. Rabi took the lead. He asked me to come to the blackboard and describe my thesis. I started off with the sentence: “The radius of the proton is 0.8 fermi.” Rabi jumped off his stool and started yelling at me: “Fermi, fermi, what is a fermi? Use the correct units. That guy has so many things named after him!” After that, I was essentially speechless. Rabi then continued: “There were so many people on your experiment. What did you do? What did you contribute?” As I was still basically speechless, I sort of mumbled: “I must have done a few things. Let me think.” Then Leon chimed in: “Mike, didn’t you propose adding the muon chambers?” “Oh yes, I did that.” “What else did you do?” Rabi asked. More silence by me. Leon: “Mike, didn’t you …”, etc. That’s how the exam went, and I passed.

The other Leon story took a much longer time to sort out. An issue in designing a muon beam was filtering the pions that decayed into muons so that the final pi/mu contamination was less than 1 part per million; and collimating the resulting muon beam (which has a range of 2 GeV per meter of iron) to a full width of 1˚. We solved the problem by using surplus navy cannons, with 1 foot inside diameter and 4 feet outside diameter, that I discovered lying in the BNL scrap yard by the railroad tracks in my daily bicycle trips around the lab. This gave rise to Leon’s famous comment that he could no longer make such collimators because he never again found a student of the right caliber.

Although I never specifically asked Leon, I naturally thought that I was the student of the right caliber that he was talking about. However, at the American Association for the Advancement of Science 2005 annual meeting, we had breakfast together by chance, at which he made it a point to tell me (without me asking) that “Nari Mistry was the student of the right caliber, because he was the only one who could stuff lead wool into the riflings of the cannon.” This was the first and last time that I saw or talked to Leon since the mid 1960s to 1980s, a period in which we had more than 20 joint publications based on several experiments at BNL and also at the CERN ISR, as described by Camilleri and di Lella above. Leon was the most creative and productive high-energy physics experimentalist of his generation and also the physicist with the best jokes.

Nari Mistry
Retired, Cornell University

I think it was January 1960 when Leon came to me, a PhD student at Columbia, and asked if I would like to work on what would come to be called the “Neutrino Experiment.” Of course I said yes, without realizing what was involved. All my grad student and postdoc friends tried to dissuade me, saying it was a very long shot and I would never finish my thesis. I waved them off and listened only to Leon.

The small group consisted of Leon, Mel Schwartz, grad student Dinos Goulianos (my friend and roommate and student of Mel), and me. Jack Steinberger and Jean-Marc Gaillard joined soon after. When the experiment became a reality at Brookhaven, we were joined by Gordon Danby. There was an iconic picture taken at Brookhaven of “the Seven.”

Leon was a wonderful mentor who didn’t micromanage. Dinos and I were asked to explore two different types of detectors to serve as massive track chambers for detecting neutrino interactions, and we were left alone to try and make things work. Soon Mel and Leon were inspired to try the new spark chambers that Jim Cronin was making at Princeton. So we all coalesced around making massive aluminum-plate spark chambers. I was left to design and perfect high-pressure, high-voltage spark gaps that could deliver voltage to several large 4 ft x 4 ft plates, while Dinos worked on designing the chambers. Leon would offer suggestions but no commands.

Leon was like a friend and parent to me. I remember once I was laid low by a terrific cold or flu. He dragged me out of bed to a Chinese restaurant and filled me full of hot-and-sour soup, which effected a miraculous cure. He took me in his car on a ski trip to Vermont with Steinberger, Gian Carlo Wick, and others. I was a total beginner. They took me up to the top at Mad River Glen, and then they all disappeared. There was no easy slope, and I fell and slid and tumbled all the way down a narrow twisting trail on my own.

During the long overnight shifts at Brookhaven, as the search went on with no neutrino events, Leon would drop in with his cigars and his jokes and encouragement. (Secretly both Dinos and I would try the cigars Leon left on the table.) He would also insist on periodically testing the timing of the coincidence circuits of the trigger counters by adding massive coils of delay cables. The cables would get all mixed up, and I would have to take it all apart and rewire it. Since I could not stop him, I had boxes made up with various lengths of cables and switches to insert delays without disconnecting anything. Then Leon could come in and play to his heart’s content, and I could reset all the switches to off at the end.

In 1988, when the Nobel Prize was awarded to Leon, Mel, and Jack for the “Neutrino Experiment,” we all met up in Stockholm again for the prize ceremony. A repeat photo of “the Seven” was taken, with us standing in the same positions but in full white-tie regalia. It’s all part of the record. Through it all, Leon always kept up his jokes and his relaxed manner, never too mighty for the ordinary folks.

I have to set right something that Mike Tannenbaum has said above in his comments: “This gave rise to Leon’s famous comment that he could no longer make such collimators because he never again found a student of the right caliber.” The joke wasn’t about me. I had long gone to Cornell by the time the cannons were used. By the time I heard it, everybody worldwide had heard it and recounted it to me. It was too late to try and convince anybody. It was always about Mike, but I guess he didn’t fit the joke because he is much bigger than I am. That is typical of Leon: The jokes meant a lot to him.

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