The 2026 Breakthrough Prize in Fundamental Physics was awarded to Muon g-2 collaborators including several University of Michigan physicists.

Three overlapping collaborations have undertaken experiments spanning more than five decades to measure a single, fundamental property with unprecedented precision: the anomalous magnetic moment of the muon. This value is helping scientists stress-test the Standard Model, physicists’ comprehensive theory of nature’s fundamental particles and forces.

“This Breakthrough Prize is awarded to teams working over decades at three labs—more than 200 individuals in all. That is what it takes to accomplish measurement of this fundamental property of muons with this precision,” said Timothy Chupp, a member of the collaboration and a U-M professor of physics and biomedical engineering. “Recognizing that it takes a village, in contrast to solitary genius, to do fundamental, cutting edge, breakthrough science is a crucial and commendable message of this selection.”

This marks the second consecutive year that U-M scientists were part of teams that claimed the Breakthrough Prize in Fundamental Physics. The award comes with a $3 million prize that will be split among the living laureates. The Breakthrough Prizes, sometimes billed as the Oscars of the Sciences, were created in 2012 by Sergey Brin, Priscilla Chan and Mark Zuckerberg, Yuri and Julia Milner, and Anne Wojcicki.

In addition to Chupp, current U-M doctoral students Eva Kraegeloh and David Aguillard are members of the Muon g-2 Collaboration, as are former postdoctoral researcher Joe Grange and alumni Midhat Farooq and Alexander Tewsley-Booth. Farooq and Tewsley-Booth both earned their doctorates at U-M in 2019.

“It has been nice to be congratulated by my colleagues, family and friends,” Chupp said of winning the prize. “But the most gratifying and immediate feelings came from being reminded that we are part of a team of so many brilliant people who really learned how to measure the muon’s g-2 and succeeded beyond expectations.”

The U-M team brought expertise and techniques from atomic, quantum and laser physics to the experiment to help study muons—subatomic particles that are like electrons, but with 200 times their mass—with unmatched precision. In particular, the team’s work has focused on measuring the magnetic field within the experiment’s large magnetic ring and calibrating the magnetic field measuring system.

“For calibration we developed a new quantum-sensor approach using lasers to control helium atoms, which we call absolute magnetometry,” Chupp said. “The accuracy of our sensors is measured in parts-per-billion.”

With contributions from U-M and dozens of other institutions, the experiment measured how fast muons “wobble” or precess under the influence of a magnetic field. The measurement provides a benchmark for scientists working to challenge the Standard Model.

The European Organization for Nuclear Research, or CERN, launched the first g-2 (pronounced “gee minus two”) storage-ring experiments in 1970. Brookhaven National Laboratory in New York then built and hosted the second-generation experiment, which ran from 1997 to 2001. In 2013, the 50-foot circumference magnet, the heart of Brookhaven’s experiment, was relocated to Fermilab, the US national particle accelerator lab near Chicago, where the apparatus was assembled for the third-generation experiment.

“The experiment was systematically refined to achieve a final precision of 127 parts per billion—a mind-boggling 30,000 times more precise than the first g-2 experiment,” said a Breakthrough Prize announcement. “This experiment represents a remarkable theoretical, experimental and technological endeavor, achieving extraordinary precision in the quest for fundamental understanding.”