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Landmarks in Particle Physics at Brookhaven National Laboratory LEGIBILITY NOTICE A major purpose of the Techni- cal Information Center is to provide the broadest dissemination possi- ble of information contained in DOE's Research and Development Reports to business, industry, the academic community, and federal, state and local governments. Although a small portion of this report is not reproducible, it is being made available to expedite the availability of information on the research discussed herein. BNL-52129 T BROOKHAVEN LECTURE SERIES Landmarks In Particle Physics At Brookhaven National Laboratory Robert K. Adair Number 238 November 18,1987 J BROOKHAVEN NATIONAL LABORATORY OF THIS DOCUMENT IS UNLIMITED BNL—52129 BNL-52129 UC-414 DE89 012916 (High Energy Physics — DOE/OSTI-4500-Interim 3) Landmarks In Particle Physics At Brookhaven National Laboratory Robert K. Adair Number 238 November 18, 1987 BROOKHAVEN NATIONAL LABORATORY Associated Universities, Inc. Under Contract No. DE-AC02-76CH00016 with the United States Department of Energy Vo. •• •' •" < DlSTRjBUTiQN OF THIS DOCUMENT iS UNLIMITED DISCLAIMER This report was prepared as an account of work sponsored by an agency of the U nited States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency, contractor or subcontractor thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency, contractor or subcontractor thereof. Printed in the United States of America Available from National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 NTIS price codes: Printed Copy: A02; Microfiche Copy: A01 Summary Robert Adair's lecture on Landmarks in Particle Physics at Brook- haven National Laboratory (BNL) is a commemoration of the 40th Anniversary of Brookhaven National Laboratory. Adair describes ten researches in elementary particle physics at Brookhaven that had a revolutionary impact on the understanding of elementary particles. Two of the discoveries were made in 1952 and 1956 at the Cosmotron. BNL's first proton accelerator. Four were made in 1962 and 1964 at the Alternating Gradient Synchrotron, the Cosmotron's replacement. Two other discoveries in 1954 and 1956 were theoretical, and strong focusing (1952) is the only techni- cal discovery. One discovery (1958) happened in an old barrack. Four of the discoveries were awarded the Nobel Prize in Physics. Adair believes that all of the discoveries are worthy of the Nobel Prize. Landmarks in Particle Physics at Brookhaven National Laboratory Robert K. Adair Both Brookhaven National Laboratory' (BNL) there were remarkable people whose contribu- and the modern discipline of Elementary Parti- tions at BNL were just as seminal, if perhaps cle Physics were born about forty years ago. not quite as singular, whom I cannot leave out Hence, their histories are entwined — and ent- of any essay I write on the history of Brook- wined with my own less significant personal haven which includes the early years. No de- history as I began graduate school at the Uni- scription of particle physics at BNL in those versity of Wisconsin, began my first research, times can stand without mentioning Lee and saw the first paper with my name as an Haworth. the one time semi-pro baseball author, also forty years ago in 1947. player, brought up in the Society of Friends in My first association with Brookhaven came Indiana, who was the leader and the Director of only a little later when 1 worked at the labora- the laboratory in the great early years. The bril- tory through the summer of 1949 as a visiting liant, idiosyncratic Oreste Piccioni, who came graduate student while preparing a review to BNL after conducting a remarkable experi- paper on neutron cross sections. A few years ment in war-time Italy that radically changed later, in 1953.1 left Wisconsin and joined the particle phyr'cs, set his stamp of originality staff of the old BNL Cosmotron Department. It and intellectual rigor on the experimental pro- was there that I began working with Larry gram. And I cannot leave unmarked the strik- Leipuner and Rich Larsen. a relationship that ing leadership provided in experimental phys- has continued for nearly 35 years through my ics by Rod Cool and Sam Lindenbaum, and in move across the water to Yale and recent return accelerator development by John Blewett and to BNL. Ken Green. Hence I have been a part of BNL for almost the whole of its existence, and the ten remark- 1. Associated Production able accomplishments I am describing here are matters I witnessed, conducted by people I Physical Review 91:1287,1953 knew well. This is then a personal account and Production of V? Particles if it is colored by my affection and respect for By Negative Pions in Hydrogen my friends who conducted these experiments, W.B. Fowler, RP. Shutt. A.M. Thorndike, so be it. and W.L. Whittemore How remarkable are these landmarks I have chosen? I can answer only by pointing out that Brookhaven National Laboratory Nobel Prizes were awarded on account of three Upton. New York of the discoveries and could well have been (Received July 16. 1953) awarded for the other seven. (Since I gave this In the course of staffing the nascent laboratory talk, the Nobel Prize has indeed been awarded with physicists who could exploit the big accel- for one of the other seven. Leon Lederman, Mel erator — to be the world's largest — under con- Schwartz, and Jack Steinberger won the 1988 struction, Ralph Shutt was brought to BNL as a prize for Number 7, the discovery of the muon special expert in diffusion cloud chambers. The neutrino). (ordinary) Wilson Cloud Chamber works by The cast of the ten-act drama I describe cooling vapor-saturated gas through expansion: includes, of course, many of the remarkable droplets then condense about gas molecules scientists who have served on the BNL staff. But electrically disturbed by the passage of high energy particles, hence, marking the particle particlcs (labeled after the V shaped tracks they tracks. Particle tracks are delineated similarly produced in the chamber) formed bv (lie inter in diffusion chambers but the saturated vapor actions ol cosmic rays. According to ideas is cooled by diffusion from warm to cold areas accepted at (he time, these si range particles in the chamber. Though both chambers work should have lived only about 10" seconds: ihcv well with accelerators, the diffusion chambers actually survived more than 10 seconds — the match accelerator cycle rates somewhat better. difference between a summer afternoon and Shutt quickly recruited a fine group of physi- the age of the universe. How could I his be cists and built a large high-pressure hydrogen understood? Shim's experiment provided a diffusion chamber in a powerful magnet. Then path to the understanding of" ihese strange with his colleagues, he used the chamber to particles. study the products of the interactions of high Figure 1 shows a remarkable picture of the energy particles at the Cosmotron, soon after vapor trails of the panicles produced by the that machine began producing protons at the interaction of a pi-meson with a proton in the unprecedented energy of 2.3 GeV. Thousands of hydrogen gas that filled the chamber. The V pictures of the chamber were taken during the shaped set of tracks is significant. From the experiment. One was wholly remarkable and small curvatures of the tracks in the magnetic served to initiate the solution of one of the field (not shown in Figure 2) the momentum of pressing problems in particle physics. the three important tracks could be deter- Some years before, the British physicists, mined. Then (as I heard the story) Shutt work- Rochester and Butler, had observed two V- ing at home in the evening on his kitchen table Figure 1. The stereophotograph shows the V-decay that consti- tuted the first evidence for asso- ciated production. was able to show that the data indicated that Hydrogen two strange particles wort- produced in the ffasion cloud interaction of the incoming pi meson; a lambda chamber particle (that produced through its decay the V shaped tracks seen in the chamber) and a par- ticle (now called a K-particle) which did not 6- K (d,S) decay in the chamber. Since both the lambda and K particles were electrically neutral, (heir A <u, d,s) passage through the gas caused no electrical disturbance and no track. P (U..LI, d) This discover}' that the strange particles were produced in pairs in an "associated produc- •n" (d,Q) tion" was a first essential step on the road that led to the description of matter as constituted by quarks. In retrospect, the BNL photograph Figure 2. At the left is a schematic reconstruc- was evidence for the existence of the s-quark tion of the event seen in the cloud chamber. The and anti-s-quark. but quarks were not under- dotted lines show the paths of neutral particles stood for another decade. Looking at the recon- that do not leave tracks. The rr TT decay at the struction of the event from the cloud chamber right in the chamber was not seen but inferred picture as shown in the diagram at the left of from analysis.
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