a new perspective
Supercomputer simulations reveal the influence of the strong nuclear force on the muon’s magnetism.
Credit: University of Wuppertal
Supercomputer simulations reveal the influence of the strong nuclear force on the muon’s magnetism.
Credit: University of Wuppertal
This latest measurement focuses on strong force effects, in particular on “hadronic vacuum polarization”, which arises as quarks and gluons interact within the framework of quantum chromodynamics (QCD) theory. The authors took a hybrid approach, combining powerful large-scale computer simulations with experimental data.
“The old method involved collecting thousands of experimental results and reinterpreting them to obtain a single number, the magnetic moment of the muon,” Fodor said. “Our approach was completely different. We divided space-time into very small cells, a lattice, then we solved the equations of the Standard Model on that. There was a lot of theory, mathematics, programming, computational knowledge and computer architecture behind this calculation.”
It took 10 years to make those complex calculations, but when they were completed. Fodor et al. Found that their results agreed with the standard model to within half a standard deviation and up to 11 decimal places. This is the most accurate calculation ever achieved, accurate to parts per billion. Although the results do not completely rule out potential new physics like the fifth power, they do further constrain areas where new physics may lie.
“People ask me how it feels to make this discovery, and to be honest, I feel somewhat sad,” Fodor said. “When we started calculating this quantity, we thought we were going to have a good and reliable calculation for a new fifth force. Instead, we found that there is no fifth force. We got a very precise proof not only of the Standard Model but also of quantum field theory, which is the foundation on which the Standard Model was built.”
Nature, 2026. DOI: 10.1038/s41586-026-10449-z (About DOI).
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