Herbert Steiner
Our colleague Herbert Steiner passed away on January 15, 2025, at the age of 97. Herb was an accomplished experimental particle physicist with diverse interests. Herb was born in Göppingen, Germany in 1927. He and his family immigrated to the US in 1938, settling in San Francisco. In 1947 he entered U.C. Berkeley as an undergraduate, and he began his graduate studies in 1951. In 1956, with his Ph.D. in hand, he became a research physicist at the U.C. Radiation Laboratory (now the Lawrence Berkeley National Laboratory) and a lecturer in the U.C. Berkeley Department of Physics. In 1961 he joined the Berkeley Physics faculty and, from 1992 to 1995, served as the chair of the department. In 2000 he became professor emeritus.
Under the guidance of Professor Emilio Segrè, Herb studied fission of heavy elements in high-energy collisions for his Ph.D. dissertation. As a graduate student, he was recognized for his important contributions to the Chamberlain-Segrè experiment at the Bevatron that discovered the antiproton in 1955, ending the debate whether it exists or not.
Group photo from Emilio Segrè's Nobel Prize conference. Seated from left to right: Glenn Seaborg, Clyde Wiegand, Emilio Segrè, Herb Steiner, and Edwin McMillan. The 1959 Nobel Prize was awarded to Emilio Segrè and Owen Chamberlain (not shown) for their discovery of the antiproton. Herb's contributions to this discovery were mentioned in Owen's Nobel lecture.
During the peak of discovering strange hadrons in the 1960s, Herb studied their intrinsic spins and parities. His effort provided crucial support for the eight-fold way that led to the quark picture, which is now a basic ingredient of the Standard Model of particle physics. Towards the end of the decade, Herb spent his sabbatical leave at CERN, working with Georges Charpak on developing multiwire proportional chambers. This Nobel-prize winning invention revolutionized the tracking of charged particles in astrophysics, nuclear and particle-physics experiments. In addition, he and Owen Chamberlain launched a series of experiments with polarized targets pioneered by them. Polarization was an interest that endured with Herb for the next three decades.
In the 1970s, the group's exploration of spin physics moved to Fermilab. In parallel, when the Bevatron began accelerating heavy ions, a new collaboration for studying heavy-ion physics grew in Berkeley. Besides Herb’s involvement, this joint venture included Shoji Nagamaya, Isao Tanihata and their colleagues from the University of Tokyo and Osaka University.
In the early 1980s Herb joined a small group led by Mark Strovink to carry out a search for the right-handed current using the decay of stopped polarized muons at TRIUMF, in Vancouver, Canada. Herb recruited Bob Tripp and George Gidal to join the collaboration. The limit on the right-handed current that they obtained remained for many years the definitive result. The publication in 1986 based on the Ph.D. thesis of Herb's student Alex Jodidio on this experiment garnered more than 300 citations.
In the modern era of particle physics with the Standard Model firmly established, Herb was actively involved in experiments at the Stanford Linear Collider. Using the SLD detector, Herb studied the production asymmetry of the Z boson in polarized electron-positron collisions and obtained a precise measurement of the weak mixing angle, one of the fundamental parameters of the Standard Model.
Following the success of the Deep Inelastic Scattering experiment at SLAC, Herb became interested in high-energy electron-proton collisions. He contributed to the publications of the H1 collaboration at the ep collider HERA and was instrumental in understanding the calorimeters. These instruments played an important role in the flurry of publications in the mid and late 1990s that led to the precise measurement of high-Q2 events in neutral and charged current reactions.
After the discovery of an atmospheric neutrino deficit, Herb turned his attention to neutrino physics. By determining the rate and energy spectrum of the electron antineutrinos coming from all the Japanese nuclear reactors with the KamLAND detector, Herb and his collaborators observed neutrino oscillation using artificial antineutrino sources for the first time. This compelling finding validated the concepts of neutrino mixing and massive neutrinos. Herb then joined Kam-Biu Luk to work on the Daya Bay reactor neutrino experiment in China, which discovered a surprisingly large value for the smallest neutrino mixing angle. He played a crucial role in the installation and testing of the detectors.
From his active involvement in the discovery of the anti-proton in the fifties to the recent participation in Daya Bay, Herb always brought his unique expertise at the critical time to an experiment. Moreover, he had a profound impact on training students, postdoctoral fellows, and the junior staff on the experiments. Herb engaged with students as a true mentor and contributed to many physics discussions, often with his characteristic and persuasive smile.
Herb was at Berkeley for 77 years. For his contributions to the Physics Department, to the “Rad Lab”, and to the broader physics community he will be remembered for many more.