Deviations from 2

A moment for muons

“…T he muon can be seen as a heavier and unstable carbon copy of the electron -so far, so unremarkable. But whereas measurements of the anomalous magnetic moment of the electron conform to our theoretical predictions 1 , those of the muon tell a different story. And as the comparison between measurement and prediction directly tests the standard model of particle physics at the level of quantum loop effects, probing this deviation may reveal as yet unknown particles.…”