A New Measurement of the Muon Magnetic Anomaly

The Muon g-2 collaboration has measured the anomalous magnetic g value, a = (g-2)/2, of the positive muon with an unprecedented uncertainty of 0.7 parts per million. The result, based on data collected in the year 2000 at Brookhaven National Laboratory, is in good agreement with the preceding data. The measurement tests standard model theory, which at the level of the current experimental uncertainty involves quantum electrodynamics, quantum chromodynamics, and electroweak in...

The Muon $g\textrm{-}2$ Experiment (E989) at Fermilab has a goal of measuring the muon anomaly ($a_\mu$) with unprecedented precision using positive muons. This measurement is motivated by the difference between the previous Brookhaven $a_\mu$ measurement and Standard Model prediction exceeding three standard deviations, which hints at the possibility of physics beyond the Standard Model. Muons are circulated in a storage ring, and the measurement requires a precise determina...

The anomalous magnetic moment of the muon is an important observable that tests radiative corrections of all three observed local gauge forces: electromagnetic, weak and strong interactions. High precision measurements reveal some discrepancy with the most accurate theoretical evaluations of the anomalous magnetic moment. We show in this note that the UV finite theory cannot resolve this discrepancy. We believe that more reliable estimate of the nonperturbative hadronic contr...

The muon g-2 experiment at Brookhaven has been taking data since 1997. Analyses of the data taken in 1997 and 1998, which include about 2% of the data taken so far, have improved the experimental accuracy in the muon anomalous magnetic moment to a(mu,expt) = 1 165 921(5) x 10**(-9) (4 ppm). The value agrees with standard theory. Analysis of the 1999 data, about 25% of the existing data set, is nearing completion and analysis of the 2000 data has started. The experiment is pre...

The calculations entering the prediction of the standard model value for the anomalous magnetic moment of the muon $a_\mu$ are reviewed, and compared to the very accurate experimental measurement. The situation for the electron is discussed in parallel.

The Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency $\omega_a$ to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run in 2018. When combined with a precision measurement of the magnetic field of the experiment's muon storage ring, the precession frequency measurement determines a muon magn...

A new experiment at Fermilab will measure the anomalous magnetic moment of the muon with a precision of 140 parts per billion (ppb). This measurement is motivated by the results of the Brookhaven E821 experiment that were first released more than a decade ago, which reached a precision of 540 ppb. As the corresponding Standard Model predictions have been refined, the experimental and theoretical values have persistently differed by about 3 standard deviations. If the Brookhav...

The muon magnetic anomaly, $a_{\mu}$, is a powerful test of the Standard Model of particle physics. A new experiment at Fermilab has recently measured $a_{\mu}$ with unprecedented precision, confirming the results of the earlier Brookhaven experiment and strengthening the tension with the prediction of the Standard Model as determined by dispersive methods. We here describe the experimental technique, recapitulate the recent result, and discuss some of the improvements made f...

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 ...

We present a new, completely revised calculation of the muon anomalous magnetic moment, $a_\mu=(g_{\mu}-2)/2$, comparing it with the more recent experimental determination of this quantity; this furnishes an important test of theories of strong, weak and electromagnetic interactions. These theoretical and experimental determinations give the very precise numbers, $$10^{11}\times a_\mu=\cases{116 591 806\pm50\pm10 ({\rm rad.})\pm30 (\ell\times\ell)\quad\hbox{[Th., no $\tau$]}\...