Francis Louis Halzen (born 23 March 1944) is a Belgian-American particle physicist and Nobel laureate. he is the Vilas Research Professor and Gregory Breit Professor at the University of Wisconsin–Madison, and also the principal investigator of the IceCube Neutrino Observatory at the Amundsen–Scott South Pole Station in Antarctica, the world's largest neutrino detector.

In 2026, Halzen was awarded the Nobel Prize in Physics "for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin."

Early life and education Francis Louis Halzen was born on 23 March 1944 in Tienen, Belgium.

He graduated from the Catholic University of Leuven, with an MSc Physics degree in 1966, a PhD in 1969, then his agrégation de l'enseignement supérieur in 1972, all at Leuven. His PhD thesis was titled "Gebroken symmetrieën van hadronen - dynamica van het PII Pl-nucleon kanaal".[https://lib.is/lbsn996766760101471/representation?libis=11:1:1& "Gebroken symmetrieën van hadronen -dynamica van het PII Pl-nucleon kanaal". Halzen, Francis (author); KUL. Faculteit wetenschappen. (other) s. n. Leuven: s.n. 1968. [Library catalogue entry, University of Leuven].

Career Between 1969 and 1971 he worked as a scientific associate at CERN. In 1972 he was appointed professor at the University of Wisconsin–Madison and the principal investigator on the AMANDA and IceCube projects.

he is the Vilas Research Professor and Gregory Breit Professor at the University of Wisconsin–Madison. He has been director of the Institute for Elementary Particle Physics Research at the university since 1984, Gregory Breit Professor since 1987, and Vilas Research Professor since 2021.

Research Halzen has been a leading scientist in the development of cosmic ray physics and astroparticle physics since the 1970s. In addition to particle physics he published many early papers on cosmic ray anomalies and quark matter, and on relations between particle physics and cosmic rays, on particles from supernovae and on muon production in atmospheric gamma-ray showers.

AMANDA

Halzen first learned about attempts by Russian scientists to detect neutrinos in Antarctica, using radio antennas at their Antarctic research station to search for electric sparks resulting from cosmic neutrinos colliding with the ice. After determining these interactions would be too weak to register, in 1987 he started working on the AMANDA project, which proposed burying an array of light sensors deep in the Antarctic ice which is clear, dark, stable, sterile and free of background light. This pilot experiment proved successful; however, their results were marred by interference from cosmic rays as well as air bubbles in the ice. This convinced him that a much larger and deeper array would be needed, and in 2005 the AMANDA project became part of its successor project, the IceCube Neutrino Observatory.

IceCube

Halzen argued for a much larger detector and secured funding from both European and American sources. He became principal investigator and co-spokesperson for the IceCube project in 2001, remaining in this position .

In 2005, his team began construction of the IceCube project, designed to be 100 times larger than AMANDA, with a total volume of and buried up to deep. After six years of construction, IceCube became fully operational in 2011. The most important result from IceCube was the clear breakthrough observation of high-energy neutrinos (about 100 times more energetic than the particles accelerated today at the world's most powerful machine, the LHC at CERN) in 2013, from as-yet-unidentified sources outside the Galaxy. This discovery has stimulated the planning and development of even larger neutrino telescopes, both at the South Pole and deep underwater.

In 2026, Halzen, the principal investigator of the project, was awarded the Nobel Prize in Physics "for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin."

Other roles Halzen has served on various advisory committees, including those for the SNO, Telescope Array and Auger-upgrade experiments, the Max Planck Institutes in Heidelberg and Munich, the ICRR at the University of Tokyo in 1983 and 1987, the US Particle Physics Prioritization Panel and the ApPEC particle astrophysics advisory panel in Europe.

Books With Alan Martin he co-authored Quarks and Leptons: An Introductory Course in Modern Particle Physics (1984), a standard textbook in particle physics.

Awards 1994: Fellow of the American Physical Society 2013: Breakthrough of the Year Award by the journal Physics World for the first-time discovery of cosmic neutrinos beyond the Milky Way 2015: Balzan Prize 2015: Giuseppe and Vanna Cocconi Prize of the European Physical Society 2018: Bruno Pontecorvo Prize for significant contribution to the IceCube detector construction and experimental discovery of high-energy astrophysical neutrinos. 2019: Yodh Prize of IUPAP 2021: Homi Bhabha Medal and Prize of IUPAP and TIFR 2024 Elected to National Academy of Sciences 2026: APS Medal for Exceptional Achievement in Research 2026: Nobel Prize in Physics "for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin”

Personal life Halzen is Belgian but also has United States citizenship. References

External links

(archive of talks at Institute for Nuclear Theory, U.S. Department of Energy & University of Washington)