Benjamin D. Day

Benjamin Downing Day (1936–2013) of Indianapolis, Indiana, received a B.A. from Wesleyan University, Middletown, Connecticut, in 1958 where he was elected to Phi Beta Kappa and Sigma Xi honor societies. In 1963, with the assistance of a National Science Fellowship, he received his Ph.D. in physics at Cornell University, where his advisor was Nobel Prize–winner Hans Bethe.

After two years of postdoctoral research at the University of California, Los Angeles, he spent the majority of his career at Argonne National Laboratory, where he was a Senior Physicist in the Physics Division. His research tested the basic notions about the behavior of nucleons in atomic nuclei. As Ruprecht Machleidt explained in his Advances in Nuclear Many-Body Theory (1999), Day’s work on the Brueckner theory of nuclear matter was an important contribution to the resolution of the 1970s “crisis in nuclear matter theory” over the apparent discrepancy of Brueckner theory results and variational calculations.

During his career he was an invited scholar at the Massachusetts Institute of Technology; Los Alamos National Laboratory; Neils Bohr Institute of Theoretical Physics in Copenhagen, as a Guggenheim Fellow; Ruhr University in Bochum, Germany; University of Oulu, Finland; and the International School of Physics “Enrico Fermi” run by the Italian Physical Society at Lake Como, Italy.