At McGill in the 1950s, in addition to appreciable teaching, Jackson found time for research on atomic processes and nuclear reactions at intermediate energies and the beginnings of his book on classical electricity and magnetism. While on leave at Princeton University, he found a fruitful collaboration with Sam Treiman and H. W. Wyld on weak interactions, particularly the various observable decay correlations in allowed nuclear beta decay involving the electron's momentum, its spin, the neutrino's momentum, and the nuclear spin that provide information about parity conservation or non-conservation and time reversal conservation or not. He also published an early paper on the then recently discovered muon-catalyzed fusion of hydrogen isotopes.
While at the University of Illinois Jackson initially continued work on weak interactions as well as strange particle interactions at low energy with Wyld and others. On sabbatical leave at CERN in 1963–64, he collaborated with Kurt Gottfried on production and decay of unstable resonances in high-energy hadronic collisions. They introduced the use of the density matrix to connect production mechanisms to the decay patterns and described the influence of competing processes on the reactions. During this period Jackson lectured at three summer schools—on dispersion relations at the first Scottish Universities Summer School in Physics, 1960; on weak interactions at the Brandeis Summer Institute, 1962; and on particle and polarization decay distributions at the Summer School of Theoretical Physics, Les Houches, 1965. He also published three books, one on particle physics, based on lectures at the Canadian Summer School in Edmonton and Jasper, 1957; the second, a small book on mathematics for quantum mechanics, and the third, also in 1962, the first edition of his text on classical electrodynamics.
Berkeley
Moving to Berkeley in 1967, Jackson taught on campus, did his research at LBNL, and served in administrative positions at both. In the formative years of the ill-fated Superconducting Super Collider project, he served as deputy director of operations of the SSC Central Design Group that did the R&D culminating on the 20 TeV design accepted by President Reagan in 1987. In the 1960s and 1970s his research alone and with students focused in journal publications and conference papers on models of high energy processes, radiative and resolution corrections for resonances in electron–positron annihilation, spin-flip synchrotron radiation and the polarization of electrons in a storage ring, and, after November 1974, the spectroscopy of the charm–anticharm particles. In 1973, he lectured again at the Scottish Universities Summer School, on hadronic interactions at high energies, and in 1976 at the SLAC Summer Institute, on charmonium spectroscopy. In 1973–74 he ran the nascent theory group at Fermilab and co-edited the proceedings of the 1973 "Rochester" Conference. In January 1977 Jackson began a 17-year stint as Editor of Annual Review of Nuclear and Particle Science. In much of the 1980s he was involved with many others in the high-energy physics community in activities aimed at the next step up in accelerators. Then in 1983 he became active in the R&D for the SSC, and on the program advisory committee for the SSC Laboratory, when it began in Texas in 1988.
Retirement years
Jackson retired from teaching in May 1995, but retained his connection with LBNL. In the 1990s and beyond his time was increasingly devoted to semi-historical talks and publications on a variety of topics, with a foray into refuting suggestions that cancer may be caused by environmental radiation stemming from ubiquitous electronics use. Noteworthy are a continuing series of papers in the American Journal of Physics on diverse topics in electromagnetism, including rebuttals of mistaken ideas. History of physics publications include the historical roots of gauge invariance, examples of the misattribution of discoveries in physics, and the editing of a sequel to R. T. Birge's history of the Berkeley Physics Department.
Students
Among his students at McGill, Hubert Reeves, a Master's student, went on to international prominence as an astrophysicist in France. John T. Donohue and Gordon L. Kane stand out among his Ph.D. students at Illinois. The Berkeley trio, Bob Cahn, Rick Field, and Chris Quigg, are prominent particle theorists.