Belgian physicist Francis Halzen wins 2026 Nobel Prize in Physics for neutrino discovery

Francis Halzen, a Belgian-born physicist at the University of Wisconsin–Madison, has been awarded the 2026 Nobel Prize in Physics by the Royal Swedish Academy of Sciences on 6 October 2026. The award recognizes his decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin. Halzen, now 82, conceived the vision of using Antarctic ice as a natural detector for neutrinos in the 1980s, presenting the concept in 1988.

The IceCube Neutrino Observatory, located at the South Pole, consists of 5,160 light sensors embedded in a cubic kilometre of Antarctic ice at depths between 1,450 and 2,450 metres. The instrument detects rare, high-energy neutrinos originating from cosmic phenomena such as supernovae, black holes, and gamma-ray bursts. When a neutrino interacts with ice, it produces charged particles that emit faint flashes of light—a telltale signal captured by the sensors. This enables researchers to trace neutrinos back to their cosmic sources, providing a unique window into extreme astrophysical events that conventional telescopes cannot easily observe.

Construction of IceCube was completed in 2011 after approximately 1.5 decades of development and a decade of construction. Within two years of operation, the observatory had detected neutrinos from beyond the galaxy with energies far exceeding those produced anywhere in the Solar System. In 2013, IceCube published its landmark discovery of astrophysical high-energy neutrinos, establishing neutrino astronomy as a new field. Subsequent detections, including evidence from active galaxy NGC 1068 and a 2023 map of high-energy neutrinos along the Milky Way plane, have demonstrated the observatory's scientific impact.

Halzen leads an international collaboration of over 450 researchers and engineers. The project includes participation from Japanese researchers at Chiba University, who contributed significantly to the 2012 high-energy neutrino discovery. Mark Pearce, Chair of the Nobel Committee for Physics, stated: "Francis Halzen has led an international team of researchers and engineers who have provided us with a fantastic instrument. His tenacity and scientific vision has paved the way for a new kind of astronomy."

Halzen was born on 23 March 1944 in Tienen, Belgium, and earned his doctorate from KU Leuven in 1969. Before joining the University of Wisconsin–Madison in 1972, where he served as a physics professor, he conducted research in particle physics and hadron symmetry breaking. He is also author of the widely-used textbook "Quarks and Leptons." The prize carries a monetary award of 12 million Swedish kronor (approximately USD 1.2 million or GBP 900,000). A highland in Antarctica has been named Halzen Mesa in recognition of his scientific contributions.