The Anomalous Magnetic Moment of the Muon
More than eighty years after the muon was first discovered, it is still a source of mystery. Indeed, experiments are underway that use muons as a window to search for new physics — a central goal of the high energy physics community. These efforts build on the tantalizing tension between experiment and theory for the muon’s magnetic moment of 3.7 standard deviations, an important hint for new physics. In particular, the recently started experiment at Fermilab aims to measure the muon’s magnetic moment with exquisite precision of 140 parts per billion, which would reduce the experimental uncertainty by a factor of four. In addition, a planned experiment in Japan will provide a completely independent measurement of this quantity. After a brief tour of its history, I will discuss the ongoing interplay between theory and experiment that is essential for unlocking the discovery potential of this effort.