Findings at Fermilab show discrepancy between theory and experiment, which may lead to new physics beyond the Standard Model.

Physicists now have a brand-new measurement of a property of the muon called the anomalous magnetic moment that improves the precision of their previous result by a factor of 2.

An international collaboration of scientists working on the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory announced the much-anticipated updated measurement on August 10. This new value bolsters the first result they announced in April 2021, and sets up a showdown between theory and experiment over 20 years in the making.