Francis Halzen

Biosketch

Francis Halzen is a Vilas Research Professor and Gregory Breit Distinguished Professor of Physics at the University of Wisconsin–Madison. Born in Belgium, Halzen received his Master’s and PhD degrees from the KU-Leuven, Belgium, and has been on the physics faculty at UW–Madison since 1972. Halzen has been a fellow of the American Physical Society since 1994 and is the recipient of numerous awards, including the 2014 Smithsonian American Ingenuity Award, the 2015 Balzan Prize, a 2018 Bruno Pontecorvo Prize, the 2019 IUPAP Yodh Prize, the 2021 Bruno Rossi Prize, the 2021 Homi Bhabha Award, and honorary doctorates at several universities. Halzen is the principal investigator of IceCube, a cubic-kilometer neutrino telescope buried in the Antarctic ice at the South Pole. IceCube’s first observations of high-energy cosmic neutrinos garnered the 2013 Physics World Breakthrough of the Year Award. In September 2017, IceCube provided the first evidence of a source of high-energy cosmic rays, whose origins have been notoriously difficult to pinpoint since they were discovered over one hundred years ago. Also a skilled science communicator, Halzen travels widely, giving about 20 or more invited talks per year at conferences, workshops, and colloquia as well as in public venues. Halzen is the co-author of Quarks and Leptons, a classic textbook on modern particle physics that continues to be used extensively throughout college campuses today. He has a large number of publications to his credit, and his essay “Antarctic Dreams,” was featured in The Best American Science Writing 2000.

Research Interests

Francis Halzen is a theoretician studying problems at the interface of particle physics, astrophysics, and cosmology. His early career coincided with the development of the Standard Model. He contributed to its early applications in collider physics and cosmic ray physics. In the mid-1980s, Halzen became interested in neutrino astronomy and battled the problem of detecting high-energy cosmic neutrinos. This led to the development at UW–Madison of experiments to use the deep Antarctic ice at the National Science Foundation’s South Pole research station as a Cherenkov detector—inaugurating the AMANDA project, which constituted the R&D platform that launched the IceCube project, transforming a cubic kilometer of ice into a particle detector. IceCube discovered a diffuse flux of extragalactic cosmic neutrinos extending to at least 10 PeV energy. The instrument presently supports a wide research program in astrophysics, neutrino physics, glaciology, and geology. It searches for dark matter as well as for other signatures of physics beyond the Standard Model. Halzen’s personal work focuses on resolving the puzzle of where Galactic cosmic rays originate by using IceCube searches. This work is guided by recent progress in pinpointing PeV-energy gamma ray sources. Halzen is also studying the first observation of extragalactic neutrino sources in a multimessenger context in order to resolve the nature of the specific sources responsible for the diffuse flux of extragalactic neutrinos and thus identify the sources of high-energy cosmic rays more than one century after their discovery.