Adrian Cho in Science:
As early as March, the Muon g-2 experiment at Fermi National Accelerator Laboratory (Fermilab) will report a new measurement of the magnetism of the muon, a heavier, short-lived cousin of the electron. The effort entails measuring a single frequency with exquisite precision. In tantalizing results dating back to 2001, g-2 found that the muon is slightly more magnetic than theory predicts. If confirmed, the excess would signal, for the first time in decades, the existence of novel massive particles that an atom smasher might be able to produce, says Aida El-Khadra, a theorist at the University of Illinois, Urbana-Champaign. “This would be a very clear sign of new physics, so it would be a huge deal.”
The measures that g-2 experimenters are taking to ensure they don’t fool themselves into claiming a false discovery are the stuff of spy novels, involving locked cabinets, sealed envelopes, and a second, secret frequency known to just two people, both outside the g-2 team. “My wife won’t pick me for responsible jobs like this, so I don’t know why an important experiment did,” says Joseph Lykken, Fermilab’s chief research officer, one of the keepers of the secret.