In memoriam: Walter R. Innes

Walt Innes

Former Fermilab scientist and, most recently, SLAC scientist Walter Innes died unexpectedly on Feb. 6.

Walt had been an integral part of the SLAC scientific community for 40 years, making many important contributions to our scientific missions in elementary particle physics. In recent years, he branched into particle astrophysics as part of the SLAC LSST Camera team.

Walt received his bachelor’s degree in physics from Caltech in 1967. After completing his Ph.D. thesis on the study of beta decays of polarized Λ baryons at the University of California, San Diego, in 1974, Walt joined Fermilab as a postdoc to work on the dimuon spectrometer (E288) proposed by Leon Lederman’s group at Columbia University. In 1977, with Walt’s improved track-finding and -fitting software and the tracking hardware that he also developed, the spectrometer’s mass resolution improved enough to produce the first evidence for the two narrow resonances, named Upsilon, bound states of a b and an anti-b quark akin to the J/psi and psi-prime (charm-anticharm quark bound states) discovered at SLAC/SPEAR just three years earlier. The Upsilon states were confirmed at the e+e storage ring at DESY later that year. The tau lepton discovered by Martin Perl in 1976 and the b quark were first evidence for the third generation of fundamental building blocks of the Standard Model — their discoveries raised many questions.

Walt’s scientific career allowed him to contribute to many of the most fundamental discoveries about the nature of matter suggested by the Standard Model. In very broad terms, his earliest contributions centered on establishing the third generation of quarks and leptons, then went on to tests of the underlying elements of the Standard Model, and in later years the open questions of physics beyond the Standard Model – dark matter and dark energy. He was fortunate to have lived through and contributed to what some physicists view as one of the most exciting and productive eras in elementary particle physics.

Walt is survived by his wife Patricia, daughters Janette Catron and Katy Mossawir, and four grandchildren. A service in honor of his life will be held on Friday, March 2, at 1 p.m. at the Sunnyvale Presbyterian Church, 728 West Fremont Avenue in Sunnyvale.

This is a version of a longer memory of Walt Innes written for SLAC’s news site.