The Muon Anomalous Magnetic Moment: A Harbinger For "New Physics"

Abstract

QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, a_mu = (g_mu-2)/2, and their theoretical uncertainties are scrutinized. The status and implications of the recently reported 2.6 sigma experiment vs.theory deviation a_mu^{exp}-a_mu^{SM} = 426(165) times 10^{-11} are discussed. Possible explanations due to supersymmetric loop effects with m_{SUSY} \simeq 55 sqrt{tan beta} GeV, radiative mass mechanisms at the 1--2 TeV scale and other ``New Physics'' scenarios are examined.