Abstract

The interaction of a muon’s spin with a magnetic field defines its magnetic moment in terms of the gyromagnetic ratio, g. In the Dirac equation, g is exactly 2, but additional higher-order QED , electroweak and strong interactions increase its value by ~ 0.1%. Moreover, new interactions beyond the Standard Model of particle physics can also contribute at the level of approximately 1 part per million. Very precise measurements are thus required to uncover new, beyond the Standard Model, interactions.

I will describe the most recent, world’s best, measurement, from the Fermilab Muon g-2 experiment: a measurement with a precision of 0.1 parts per million which is the most accurately measured quantity using a particle accelerator storage ring and the plans to improve the Standard Model prediction which will hopefully resolve whether the magnetic interaction of a muon is a harbinger of new physics or not.