Experimental physicist Robert J. Cence of Honolulu passed away peacefully at home at age 92 on 17 April 2023 after a brief illness.
Bob was born in Cleveland, Ohio, on 16 July 1930 and moved with his family to California during the Great Depression. He attended the University of California, Berkeley, where he fell in love with physics and continued on in one of the nation's top schools in physics to earn an undergraduate degree in physics in 1952 and a PhD, under the guidance of Burton Moyer, in 1960. The title of his thesis was “Photoprotons produced by 245 ± 15 MeV gamma rays on carbon.” After a postdoc at Berkeley, he was recruited in 1963 to help build a newly formed PhD program in nuclear and particle physics at the University of Hawaii at Manoa. He was one of the first hires to this program after statehood. This was the beginning of the University of Hawaii High Energy Physics Group, which was initially made up of V. Z. Peterson, Cence, and V. J. Stenger.
Bob published Pion Nucleon Scattering in 1969, which continues to be an important reference and is still available from Princeton University Press.
In Hawaii, Bob engaged graduate students Richard Morgado and Leroy Shiraishi to work on an experiment to search for Ke4 events, which are decays of K mesons into two pi mesons, an electron, and a neutrino. The experiment took place at the Berkeley Bevatron accelerator, which was famous for the discovery of the antiproton. The experiment and the analysis of the data continued through the early 1970s. The amount of data was quite large for the day, and Bob arranged with the director of computing to take over the University of Hawaii Computing mainframe IBM computer in the off hours for the data reduction. Although the original search was not entirely successful, papers were published on details of some of the apparatus involved in the experiment and in “Search for the rare decay K+→ π+e+e-.”
In the early 1970s, the expanded Hawaii team joined forces with a Berkeley group under M. L. Stevenson to propose building a device to identify muons coming from neutrino interactions in the 15-foot Bubble Chamber, then under construction at Fermilab. The device was called the External Muon Identifier (EMI). The proposal was accepted, and this led to a many-year project to construct multiwire proportional chambers with delay line readout to be mounted on the back of the bubble chamber behind a wall of zinc to filter out hadrons. The EMI was a success and led to Hawaiian participation in a series of Bubble Chamber collaborations over a 12-year period with groups from Wisconsin, Michigan, UC Berkeley, Washington, and Fermilab.
Not only did the Hawaii group help construct the EMI, but it also set up a state-of-the-art measurement facility in Hawaii to measure the bubble chamber film. Everyone worked hard on all these activities. Bob took early charge of the scanning effort. He worked hard on the analysis of the e–mu events seen first in the E28 collaboration with Jack Fry, Ugo Camerini, and Don Reeder of Wisconsin. These events were early evidence for the neutrino production and decay of charmed quarks. Later Bob worked on the analysis of electron neutrino events and the calculation of backgrounds in the neutrino data due to hadronic interactions in the bubble chamber.
The final experiment in the 15-foot Bubble Chamber, E632, took place at the Fermilab Tevatron with new groups, including many from Europe. An added feature was the use of holography.
Finally, Bob joined the Mark II experiment at SLAC, first at the PEP collider and later at the SLC. The Hawaii group, especially Sherwood Parker, played a major role in the development of the early and innovative silicon strip vertex detector installed at the SLC.
Some of Bob's greatest feats were not directly physics. He led the effort to set up text processing by computer for physics papers and proposals. Bob was one of the editors of the Proceedings of the Ninth Topical Conference in Particle Physics in 1983. This was one of the famous Hawaii Summer Schools. One of the lecturers that year was Carlo Rubbia, who was destined later to receive the Nobel Prize for the discovery of the W and Z bosons at CERN and to become director of CERN. Carlo was known for being too busy to write up talks for proceedings, but Bob pursued Carlo mercilessly day and night by telephone and by mail until the proceedings contribution arrived.
Another great feat occurred later during the E632 bubble chamber experiment. Douglas Morrison from CERN was the spokesman for the experiment, and he sent out extensive handwritten notes after each collaboration meeting. After being bombarded by many of these, Bob informed Douglas that he had to learn to type his notes on the computer and send them by email. We would no longer bother to read his illegible notes. Douglas obliged and began sending out long email messages summarizing the collaboration meetings. Later Douglas graduated to sending out long tomes on subjects like cold fusion and mad cow disease to the whole world.
Bob spent his career doing research, teaching, and mentoring physics students. In 1991 Bob received his greatest academic honor, the Presidential Citation for Meritorious Teaching. In his spare time, Bob loved to garden, hike the valleys of Kauai, camp at Bellows or Nanakuli beaches, travel with his family, play the piano, or tutor inmates at Halawa Correctional Facility. For the latter, Bob received the First Lady’s Outstanding Volunteer Award from Mrs. George R. Ariyoshi in 1983.
Bob retired in 1996 and began to do real estate with his wife Helena. However, his interest in physics continued, and he was a regular attendee at the physics department colloquia up until the pandemic.
Bob is survived by Helena, six children, seven grandchildren, and two great-grandchildren. To honor Bob’s legacy, his family has established the Robert J. Cence Equity and Access Fund #130-2770-4 at the University of Hawaii Foundation to support first-generation college students.
Bob and his sense of humor will be solely missed.
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