George A. Key worth, Science Adviser to President Reagan and Director of the President's Office of Science and Technology Policy, speaking at the SLAC anniversary — 'a deep personal pleasure to pay tribute to the powerful impact this excellent laboratory has had on the world's science'.
very much on top of the prediction for b c, and an upper limit of 9 per cent is obtained for the ratio b -> u/b -> c. By studying how the results depend on the mass of the u quark hadrons, the CLEO group finds that the results are insensitive to masses below about 1 GeV. Upper limits for the ratio of branching ratios of 9 per cent are obtained by the CLEO group from both their muon and their elec tron spectra. These three measurements estab lish that the b quark decays predo Robert Hofstadter in his Nobel prize enormously useful to particle phy minately into c quarks, rather than u winning study of the structure of the sics and has spawned nearly 20 ma quarks. This results in a significant proton, and finally to the beginnings chines of increasing size. The most improvement of our knowledge of of the Two Mile Linac with the an prolific has been SPEAR, a ring built the parameters of the six-quark mod nouncement of support for the pro at SLAC in 1972. Richter shared the el. With the larger data samples that ject by President Eisenhower in Nobel prize of 1976 for his work in will become available, is should be 1957. the discovery of the charmed quark possible to measure the b u frac SLAC Director Pief Panofsky con and the development of this new tion from the lepton spectrum. tinued the story through the years of technique. A new kind of machine construction of the enormous pro using the colliding beam idea is now STANFORD ject which was 30 times larger than being planned at SLAC so this study existing machines of the kind. Many can continue past the present practi Anniversary time problems broke new ground in areas cal limits. Five physicists whose work spans requiring the cooperation of the uni Sidney Drell presided over this fifty years of experimental and theo versity staff with industry. New symposium on electron physics. retical study in particle physics ways of managing the powerful Theoretical work by Drell has been spoke at the recent multiple anniver beams of up to one megawatt were very important both in the exploita sary celebration of the Stanford Li needed. tion of secondary particle beams as near Accelerator Center. James Bjorken, now at Fermilab, well as in understanding many of the This multiple anniversary marked reviewed the theoretical and exper experimental results. As Deputy Di 35 years of electron linacs, 25 years imental work which has resulted rector of SLAC he heads the theore since the launching of the proposal from these intense electron beams. tical section, which has students and for the SLAC linac, 20 years since the A series of theories were used to researchers from around the world. beginning of the linac construction, understand the ways in which elec 15 years since the linac achieved its tron and photon beams actually Accelerator Summer design energy, 10 years of SPEAR probe the structure of matter. Much operation, and 5 years since the be of this culminated in the understand School ginning of PEP construction. ing of the unexpected results ob Approximately 150 physicists and Edward Ginzton traced the begin tained with SLAC's giant spectro engineers from the United States, nings of the linear accelerator work meters in electron scattering on hy Canada, Europe and Asia spent two at Stanford from ideas of young stu drogen. This led to the parton picture weeks at SLAC in the Second Sum dents with $100 to spend on mate of pointlike constituents in the pro mer School on High Energy Particle rials, to the famous klystron tubes ton and neutron. Accelerators. The school was spon which have found great use in radar Burt Richter discussed the inven sored jointly by the US Department and other microwave work, to a sec tion of storage rings with its begin of Energy (DOE), the US National tion of accelerator which could be nings as the Princeton-Stanford elec Science Foundation, and SLAC. M. carried on a man's shoulder, to the tron rings on the campus. The tech Month of DOE was Chairman of the Mark 3 Linac at Stanford used by nique of colliding beams has proven Organizing Committee and G. Loew
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