Renewed measurements of muon's magnetism could open door to new physics

Science (Jan. 25) -- Next week, physicists will pick up an old quest for new physics. A team of 190 researchers at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, will begin measuring to exquisite precision the magnetism of a fleeting particle called the muon. Because the muon can emit and reabsorb any particle, its magnetism tallies all possible particles—even new ones too massive for the LHC to make. Other charged particles could also sample this unseen zoo, says Aida El-Khadra, a theorist at the University of Illinois in Urbana. But, she adds, "The muon hits the sweet spot of being light enough to be long-lived and heavy enough to be sensitive to new physics."