Theoretical physicists at the U.S. Department of Energy’s (DOE’s) Brookhaven National Laboratory and their collaborators have just released the most precise prediction of how subatomic particles called muons—heavy cousins of electrons—”wobble” off their path in a powerful magnetic field. The calculations take into account how muons interact with all other known particles through three of nature’s four fundamental forces (the strong nuclear force, the weak nuclear force, and electromagnetism) while reducing the greatest source of uncertainty in the prediction. The results, published in Physical Review Letters as an Editors’ Suggestion, come just in time for the start of a new experiment measuring the wobble now underway at DOE’s Fermi National Accelerator Laboratory (Fermilab).