Jerome Friedman The Nobel Prize in Physics

biography

One of the most important tasks of physics is to provide us with a clearer picture of the world we live in. We know that the observable universe is much larger than any of us could imagine and is even, perhaps, no more than just an island in an ocean of universes. But the creation also has another unfathomable frontier - that towards smaller and smaller constituents: molecules, atoms and elementary particles.

It is the business of science to probe elementary particles as well as the most remote galaxies, collecting facts and deciphering relationships at all levels of creation. The amount of information increases rapidly and without understanding can become overwhelming. Such confusion prevailed at the end of 1950s. At the deepest level of the microscopic world were the electron, the proton and the neutron, particles which for years had been considered to be the fundamental building blocks of matter. However, they were no longer alone but were accompanied by many newly discovered particles. The special roles of the proton and the neutron are evident among other things they are responsible for more than 99 percent of our weight. But what roles did the other particles play? Where had nature's elegance and beauty gone? Was there a hidden order not yet discovered by man? There could be order but only at the price of postulating an additional, deeper level in nature - perhaps the ultimate level - consisting of only a few building blocks. Such an idea had been advanced and the new building blocks were called "quarks" - a word borrowed by the 1969 Nobel Prizewinner in Physics, Murray Gell-Mann, from "Finnegans Wake," for most of us an incomprehensible masterpiece by the great Irish novelist James Joyce. But the quark hypothesis was not alone. There was, for example, a model called "nuclear democracy" where no particle had the right to call itself elementary. All particles were equally fundamental and consisted of each other.

This year's Laureates lit a torch in this darkness. They and their coworkers examined the proton (and later on also the neutron) under a microscope - not an ordinary one, but a 2 mile-long electron accelerator built by Wolfgang K.H. Panofsky at Stanford, California. They did not anticipate anything fundamentally new: similar experiments, albeit at lower energies, had found that the proton behaved like a soft gelatinous sphere with many excited states, similar to those of atoms and nuclei. Nevertheless, the Laureates decided to go one step further and study the proton under extreme conditions. They looked for the electron undergoing a large deflection, and where the proton, rather than keeping its identity, seized a lot of the collision energy and broke up into a shower of new particles. This socalled "deep inelastic scattering" had generally been considered to be too rare to be worth investigating. But the experiment showed otherwise: deep inelastic scattering was far more frequent than expected, displaying a totally new facet of proton behavior. This result was at first skeptically received: perhaps the moving electron gave off undetected light. But this year's Prizewinners had been thorough and their findings were subsequently confirmed by other experiments.

The interpretation was given primarily by the theorists James D. Bjorken and the late Richard P. Feynman (Feynman stood in this Hall exactly 25 years ago to receive a Nobel Prize for another of his great contributions to physics). The electrons ricocheted off hard point-like objects inside the proton. These were soon shown to be identical with the quarks, thus simplifying the physicist's picture of the world; but the results could not be entirely explained by quarks alone. The Nobel Prize-winning experiment indicated that the proton also contained electrically neutral constituents. These were soon found to be "gluons," particles glueing the quarks together in protons and other particles. A new rung on the ladder of creation had revealed itself and a new epoch in the history of physics had begun

I was born in Chicago, Illinois on March 28, 1930, the second of two children of Selig and Lillian Friedman, nee Warsaw, who were immigrants from Russia. My father came to the United States in 1913 and later served in the U.S. Army Artillery Corps in World War I. After the war he was employed by the Singer Sewing Machine Co. and later established his own business, repairing and selling used commercial and home sewing machines. My mother arrived in the United States in 1914 on one of the last voyages of the Lusitania. She supported herself until she was married by working in a garment factory. My parents had little formal education, except for courses in English after they arrived in the United States, but were self taught and had wide ranging interests. My father was an avid reader, having interests in science and political history, and our home was filled with books. My mother, who had a lovely singing voice, loved music and, in particular, opera. The education of my brother and myself was of paramount impor tance to my parents, and in addition to their strong encouragement, they were prepared to make any sacrifice to further our intellectual development. When there were financial difficulties they still managed to provide us with music and art lessons. They greatly respected scholarship in itself, but they also impressed upon us that there were great opportunities available for those who were well educated. I received my primary and secondary education in Chicago. As I very much liked to draw and paint as a child, I entered a special art program in high school, which was very much like being in an art school imbedded in a regular high school curriculum. While I always had some interest in science, I developed a strong interest in physics when I was in high school as a result of reading a short book entitled Relativity, by Einstein. It opened a new vista for me and deepened my curiosity about the physical world. Instead of accepting a scholarship to the Art Institute of Chicago Museum School

and against the strong advice of my art teacher, I decided to continue my formal education and sought admission to the University of Chicago because of its excellent reputation and because Enrico Fermi taught there. I was fortunate to have been accepted with a full scholarship. As my parents had limited means, my university training would not have been possible without such help. After finishing my requirements in an highly innovative and intellectually stimulating liberal arts program (established by Robert M. Hutchins who was then President of the University), I entered the Physics Department in 1950, receiving a Master's degree in 1953 and a Ph.D. in 1956. It is difficult to convey the sense of excitement that pervaded the Department at that time. Fermi's brilliance, his stimulating, crystal clear lectures that he gave in numerous seminars and courses, the outstanding faculty in the Department, the many notable physicists who frequently came to visit Fermi, and the pioneering investigations of pion proton scattering at the newly constructed cyclotron all combined to create an especially lively atmosphere. I was indeed fortunate to have seen the practice of physics carried out at its "very best" at such an early stage in my development. I also had the great privilege of being supervised by Fermi, and I can remember being overwhelmed with a sense of my good fortune to have been given the opportunity to work for this great man. It was a remarkably stimulating experience that shaped the way I think about physics. My thesis project was an investigation in nuclear emulsion of proton polarization produced in scattering from nuclei at cyclotron energies. The objective was to determine whether the polarization resulted from elastic or inelastic scattering. Professor Fermi tragically died in 1954 after a short illness. What an immense loss it was to all of us. My thesis work was not yet completed, and John Marshall kindly took over my supervision and signed my thesis. After I received my Ph.D., I continued working as a post-doc at the

University of Chicago nuclear emulsion laboratory, which was then led by Valentine Telegdi. That year Val Telegdi and I did an emulsion experiment in which we searched for parity violation in muon decay. We were one of the first groups to observe this surprising effect which had been suggested by T.D. Lee and C.N. Yang. Val was not only an excellent mentor but he was instrumental in getting me my first real job with Robert Hofstadter.