SLAC - PUB - 7049 March 1996 Reflections on the Discovery of the Tau Lepton ’

My first thoughts in writing this lecture are about the young women and young men who are beginning their lives in science: students and those beginning scientific research. I have been in experimental scientific research for 45 years; I have done some good experiments of which the best was the discovery of the tau leptonj I have followed research directions that turned out to be uninteresting I have worked on experiments that failed. And so while recounting the discovery of the tau for which I have received this great honor, I W try to pass on what I have learned about doing experimental science. I begin my reflections by going back in time before the tau, before even my interest in leptons. I was trained as an engineer at Polytechnic University (then the Polytechnic Institute of BrooMyn) and I always begin the design of an experiment with engineering drawings, with engineering calculations on how the apparatus is to be built and how it should work. My strong interest in engineering and in a mechanical view of nature carried over into my career in physics. My doctoral thesis research (Perl, Rabi, and Senitzky 1955) was carried out at Columbia University in the early 1950’s under Professor Isidor Rabi. The research used the atomic beam resonance method invented by Rabi, for which he received a Nobel Prize in 1944. My experimental apparatus, Fig. 1, was boldly mechanical with a brass vacuum chamber, a physical beam of sodium atoms, submarine storage batteries to power the magnets— and in the beginning of the experiment, a wall galvanometers to measure the beam current. I developed much of my style in experimental science in the course of this thesis experiment. When designing the experiment and when thinking about the physics, the mechanical view is always dominant in my mind. More important, my thinking about elementary particles is physical and mechanical. In the basic production process for tau leptons