Professor Charles F. Perdrisat, a William & Mary physicist, has been awarded the 2017 Tom W. Bonner Prize in Nuclear Physics.
The Bonner Prize, awarded by the American Physical Society, is widely regarded as one of the greatest honors a nuclear physicist can receive. The APS site notes that the purpose of the award is “to recognize and encourage outstanding experimental research in nuclear physics, including the development of a method, technique or device that significantly contributes in a general way to nuclear physics research.”
“It is grand to see Professor Perdrisat receive this singular distinction for his extraordinary contributions to nuclear physics,” said W&M President Taylor Reveley. “His work has given us a better understanding of the structure of the proton, one of the building blocks of matter, with implications for understanding the early formation of matter in the known universe. William & Mary is very proud of Charles.”
Perdrisat was recognized for his experimental work done over 25 years at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News. He is currently professor emeritus of physics at William & Mary, where he has been a member of the Department of Physics faculty since 1966. He was nominated for the Bonner Prize by his long-time colleague in the physics department, Carl E. Carlson.
The award citation reads that Perdrisat is recognized “for groundbreaking measurements of nucleon structure, and discovering the unexpected behavior of the magnetic and electric form factors of the proton with changing momentum transfer in electron-proton scattering.”
Perdrisat explained that form factors describe the spatial distribution of electric charge and current in an elementary particle like the proton (which is the nucleus of the hydrogen atom). In the case of his research, the target objects are protons. Until recently, form factors have been obtained almost exclusively from measured probability of scattering of electrons on nucleons. In the JLab experiments, a different technique has been used, resulting in unexpected results.
“In the technique we used at JLab, we sent polarized electrons on an un-polarized hydrogen target, and measured the polarization of the recoiling proton,” he said. “The amount of polarization transferred from the electron to the proton tells us the value of the ratio of the two form factors.”
The three experiments done so far at JLab, increasing the momentum transfer each time, were the results of a collaboration with V. Punjabi of Norfolk State University, M.K. Jones of JLab, E.J. Brash of Christopher Newport University and L. Pentchev of JLab.
The Bonner Prize comes with a $10,000 honorarium and an invitation to give a talk on his work at the American Physical Society meeting to be held Jan. 28-31 in Washington, D.C.
The honoree holds the Doctor of Natural Science degree from the Federal Institute of Technology, Zurich (1962). In addition to his long career at William & Mary, Perdrisat served as a visiting professor at the Federal Institute of Technology in Zurich, Switzerland (1973-1974), as well as in the Institut de Physique Nucléaire, in Orsay, France (1982-1983). He has been a visiting scientist at JLab on a number of occasions. He was named a fellow of the American Physical Society in 1992.
Perdrisat has a long list of well-cited publications to his credit, along with millions of dollars in external support from the National Science Foundation and Department of Energy. He became emeritus faculty in 2016, and taught a number of classes and labs in the physics department, notably Classical Dynamics, Modern Physics Laboratory and Cosmology.
Perdrisat is not the first William & Mary physicist to be awarded the Bonner Prize. Robert McKeown won the honor in 2009, as did John Dirk Walecka in 1996. Like Perdrisat, both McKeown and Walecka did extensive work at JLab and indeed both held the title of Governor's Distinguished CEBAF Professor of Physics at the university.