Richard Breedon - 1988


A measurement of the proton-proton and proton-antiproton elastic scattering

at center of mass energy 24.3 GeV with silicon barrier detectors


In experimental high energy physics, questions about the basic structure of matter are answered through the study of subatomic particles.We learn about particles in the same way we learn about people: we observe their individual behavior or, most importantly,we study their mutual interactions.

Particle interactions, like interactions among people, can be violent, resulting in drastic changes of direction, breakup, and production of new forms of matter; or can be very subtle, the particles barely ``feeling'' one another, the only result of the interaction being a slight change in direction.

This last type of interaction, known as small angle elastic scattering, is the subject of Richard Breedon's thesis. Specifically, Richard compared proton-proton and antiproton-proton elastic scattering, looking for small differences in the behavior of matter and antimatter. The forces responsible for small angle scattering are the well known electromagnetic force and the so-called strong force.Since the effect of the electromagnetic force can be predicted exactly, such experiments provide information about the strong force, which is primarily responsible for the inner structure of the particles involved.

Elastic scattering, although conceptually the simplest, is not necessarily the easiest experiment to perform. The difficulty of an experiment depends on its accuracy. Richard's experiment is perhaps the most precise of its kind. He used apparatus designed and constructed here at the University, flown to Geneva, Switzerland, and installed at the world's largest particle accelerator at the time. The data collected were then flown back to Rockefeller for painstaking analysis. The entire process required diverse hardware and software skills, determination, and patience. It is these qualities that enabled Richard to produce an extremely precise and well-documented result, showing that the behavior of protons and antiprotons becomes more similar as their energy increases. Results like this are used to provide yet another notch in the key that will eventually unlock the door to understanding the structure of matter.

Richard came to us with a Master's degree from the Universiy of Rochester. However, he didn't just drive down the New York State Thruway from Rochester: he came via Alaska, where he spent some time at the Alaska Pacific University as acting director of public affairs. This versatility would not surprise the students of the yoga class he has been teaching at the University or those of us who have seen him racing his bicycle in Central Park.

Richard will stay with the University another six months and then continue basic particle physics research at today's highest energy electron-positron collider, in Japan.

Mr. President, it is a great pleasure to present to you an accomplished physicist and a valuable colleague, Richard Bdeedon, for the degree of Dr. of Philosophy.