Department of Physics
Research, teaching and outreach in Physics at UW–Madison

Congratulations to Prof. Wu on her retirement!

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Sau Lan Wu | Photo: Jeff Miller, UW–Madison

Congrats to UW–Madison physics Prof. Sau Lan Wu, who announced her retirement effective January 1, 2026. One of the first two women on the physics faculty when she joined as an assistant professor in 1977, her nearly 50-year career stands as one of the most consequential in modern experimental particle physics.

“Sau Lan is truly remarkable and irreplaceable,” says UW–Madison experimental particle physicist and department chair Kevin Black. “If I accomplish even one-third of what she has in her career, I will consider myself incredibly successful.”

Rising from humble beginnings in Hong Kong to becoming a central figure in high energy physics, Wu’s path began at Vassar College, where she graduated summa cum laude in 1963. She then earned her MA and PhD from Harvard, part of the first cohort of women ever awarded graduate degrees directly from the university. After a postdoctoral fellowship and research appointment at MIT, she joined UW–Madison as an assistant professor in 1977, was promoted to associate professor in 1980, and to full professor in 1983. She earned the UW–Madison titles of Enrico Fermi Professor, Hilldale Professor, and Vilas Professor.

From her earliest days in the field, Wu gravitated toward the biggest scientific frontiers. She played key roles in three landmark particle discoveries: the charm quark in 1974 as part of Samuel Ting’s MIT/Brookhaven team; the gluon in 1979 through her pioneering work identifying three-jet events at DESY; and the Higgs boson in 2012, where her ATLAS group helped lead analyses of the H→γγ and H→ZZ*→4ℓ decay channels. Each discovery reshaped the Standard Model, and collectively they earned her a reputation as one of particle physics’ most influential experimentalists.

a group of very happy scientists pose for a shot, all holding a printout of the same graph
The UW–Madison ATLAS group at CERN at the time of the Higgs discovery all celebrated with printouts of the data confirming 5sigma. | Provided by Sau Lan Wu

Wu is a Fellow of the American Physical Society and the American Academy of Arts & Sciences, a recipient of the European Physical Society Prize, and shared the 2025 Breakthrough Prize in Fundamental Physics with the LHC collaboration. In 2022, the International Astronomical Union named a minor planet, Saulanwu, in her honor.

Through all these achievements, Wu remained devoted to guiding the next generation of experimental physics. 65 doctoral students completed their PhDs in her group, on major experiments from PETRA to LEP, BaBar, and the LHC. Of her former students and postdocs, 40 now hold faculty positions worldwide, and 18 are permanent staff scientists at major laboratories. Many others have gone on to high-impact roles in national science policy and the technology sector.

Says Steve Ritz, distinguished professor of physics at the University of California Santa Cruz and the Santa Cruz Institute for Particle Physics and a former student with Wu:

“Sau Lan pointed the way toward the most interesting questions, and she made sure we had what we needed for success. We always knew that we could try new approaches to problems and that she had our backs if we hit a bump in the road. She also made sure we didn’t just bury ourselves in our own work: there seemed to be a constant flow of great physicists visiting the group, and Sau Lan introduced us to each one. We were encouraged to attend their seminars and we were invited to lunch and dinner discussions. I now understand that Sau Lan was helping us develop our own sense of belonging in the field, while also pushing us to reach our full potential.”

John Conway, distinguished professor in the Department of Physics and Astronomy at UC Davis and former postdoc in Wu’s group, adds:

“I worked with Sau Lan as a postdoc on the ALEPH experiment at CERN for over five years. It was a fantastic time — her group was super lively and carrying out a lot of different work on the experiment, and which was then brand new. Sau Lan instilled in me the hunger for discovery that I have carried through the rest of my career, and demonstrated what it meant to be truly dedicated to this work. She was an inspiring leader and had genuine concern for the lives and careers of everyone who worked for her. I’ve tried to pay that forward in my own career.”

a screenshot of a newspaper front page, with an artistically-rendered photo of 5 key scientists involved in the Higgs discovery
Sau Lan Wu and other Higgs scientists were featured on the cover of the New York Times for a story about the chase for the Higgs boson.

Even in the later stages of her career, Wu remained at the forefront of innovation. She championed the integration of artificial intelligence and machine learning into experimental physics, leading ATLAS’s first event-level anomaly detection study and advancing GNN-based tracking, GAN-based simulation, and early quantum machine learning applications for high energy physics. These efforts have helped prepare the field for the data-intensive future of the HighLuminosity‑ LHC beginning later this decade.

Wu has been featured on the front page of The New York Times, profiled in Quanta and Wired, invited to write for Scientific American, and highlighted in seven books celebrating scientific trailblazers and women in STEM, many aimed at sharing the excitement of discovery with children. The UW–Madison alumni magazine, On Wisconsin, featured her in a lengthy profile in 2019. She has delivered Vassar’s 150th Commencement Address, appeared on the cover of the AIP History Newsletter, and continued to be a sought-after speaker, including keynotes at SLAC in 2024 commemorating the 50th anniversary of the J/ψ discovery.

“Sau Lan is a legend in the field of experimental particle physics,” says Sridhara Dasu, an experimental particle physics professor at UW–Madison. “Her experiences will be inspiring for generations to come.”

 

Theoretical physicist Prof. Charles Goebel has passed away

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a man and woman stand next to each other
Charlie Goebel and his wife, Belle, at a department function in 2003.

UW–Madison professor emeritus of physics Charles (Charlie) Goebel passed away February 18, 2026. He was 95.

Born, raised, and educated in Illinois, Goebel received a PhD in 1956 from the University of Chicago under the direction of the well-known quantum field theorist Gregor Wentzel. After a post-doctoral position at the Lawrence Radiation Laboratory at the University of California (now Lawrence Berkeley National Lab), he joined the faculty at the University of Rochester. In 1961, he joined the physics faculty at UW–Madison as an associate professor. He was elected a Fellow of the American Physical Society in 1963, promoted to full professor in 1964, and remained a valued member of the faculty until his retirement in 2003.

Goebel had extraordinarily diverse interests in theoretical physics, mostly centered in particle physics, field theory and general relativity. Among his most notable contributions were:

  • A method for using pion-nucleon scattering to extract the fundamental, but difficult to measure, characteristics of pion-pion scattering. This method (independently discovered by Chew and Low) was of central importance for numerous experiments in the 70s and 80s.
  • The invention of G-parity which generalizes the concept of charge conjugation parity to iso-spin multiplets. This has been a useful, and often a crucial, tool in the analysis of strong interactions.
  • The generalization of the famous Veneziano formula to N particles. The Veneziano formula was the starting point in the subsequent development of string theory.

In recommending Goebel for emeritus status, the Physics Department Executive Committee praised him for generously offering insights and advice on teaching and research questions, a thought echoed by several of Goebel’s former colleagues.

“Charlie, as we liked to call him, was a legend in the physics department in numerous ways,” says physics professor Vernon Barger. “I liked to think of him as the physicist’s physicist for his generosity in helping numerous faculty to solve their most difficult research and teaching questions.”

Adds physics professor emeritus Louis Bruch, “Charlie was able to produce ingenious solutions to a great variety of problems and provide important perspective on them.”

Goebel became legendary among generations of graduate students to whom he taught field theory, relativity, and many other subjects. Many remember — some fondly, but all with clarity — his challenging take-home exams.

Goebel loved the outdoors, including hiking, canoeing and camping, preferably in remote areas including the Boundary Waters. He hiked and biked all around Madison and walked to work in all weathers. He loved classical music, and played French horn with family and friends, something physics professor emeritus Bill Friedman recalled fondly:

“Both Charlie and I were players of brass musical instruments, he the French horn and I the trumpet. In the early 1970s, we would occasionally get together to play with a few other wind players from the department, along with Charlie’s son, John, on oboe. This was for our own amusement. We sometimes played from string quartet scores. Charlie provided me with copies of several horn pieces which I enjoyed playing on my own instrument.”

After retiring, Goebel still visited the department nearly every day until 2020, when the COVID-19 pandemic limited building occupancy. He also returned to teach Physics 831, Advanced Quantum Mechanics in Fall 2010.

Please visit the department’s tribute page to Charlie to submit and/or read stories from his colleagues.

Parts of this obituary were taken from department archives. We also thank Prof. Goebel’s family for providing additional information.

Mark Saffman named “Outstanding Referee” for American Physical Society journals

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Mark Saffman

Congrats to Prof. Mark Saffman on being named a 2026 Outstanding Referee of the American Physical Society journals!

The highly selective Outstanding Referee program annually recognizes about 150 of the roughly 56,000 referees who have been asked to review one or more papers in the last twelve months. Like Fellowship in the APS, this is a lifetime award.

In this year, 2026, 156 Outstanding Referees were selected. APS Editors select the honorees based on the quality, number, and timeliness of their reports, without regard for membership in the APS, country of origin, or field of research. Referees are rewarded for their work carried out since 1978, the earliest year for which we have accurate data on referee reports returned. The decisions are difficult and there are many excellent referees who are still to be recognized.

The Outstanding Referee program was instituted in 2008 to recognize scientists who have been exceptionally helpful in assessing manuscripts for publication in the APS journals. By means of the program, APS expresses its appreciation to all referees, whose efforts in peer review not only keep the standards of the journals at a high level, but in many cases also help authors to improve the quality and readability of their articles – even those that are not published by APS.

Other current UW–Madison physics department members who are recipients of this honor include Baha Balantekin (2024), Mark Friesen (2023), Lisa Everett (2021), Deniz Yavuz (2013), and Thad Walker (2009).