New physics behind the new muon g-2 puzzle?

The New Muon g − 2 Experiment at Fermilab

Experiment E989 is under preparation at Fermilab, intending to measure the anomalous magnetic moment of the muon gμ − 2 to an accuracy of 140 ppb, a fourfold improvement over the Brookhaven E821 result. The latter differs by more than 3 standard deviations from Standard Model predictions, perhaps hinting at new physics and motivating a more sensitive comparison. The techniques of the new experi...

The New Muon g−2 Experiment at Fermilab

Muon g − 2 and precision electroweak physics in the MSSM

The minimal supersymmetric extension of standard model (MSSM) is examined by analyzing its quantum effects on the precision electroweak measurements and the muon g − 2. We examine carefully the effects of light charginos and neutralinos that are found to improve the fit to the electroweak data. We identify two distinct regions on the (μ,M2)-plane that fit well to the electroweak data and give s...

The Muon Anomalous Magnetic Moment: A Harbinger For “New Physics”

QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, aμ ≡ (gμ − 2)/2, and their theoretical uncertainties are scrutinized. The status and implications of the recently reported 2.6 sigma experiment vs. theory deviation a μ − a μ = 426(165) × 10 are discussed. Possible explanations due to supersymmetric loop effects with mSUSY ≃ 55 √ tan β GeV, radiat...

New Physics behind the Standard Model ’ s door ? ∗

We review the main reasons pushing us beyond the SM and we argue in favor of new physics at the electroweak scale (hence experimentally accessible at present or near–future machines). We focus on the appealing possibility that such new physics is given by a super-symmetric (SUSY) extension of the SM. We discuss the minimal case, Constrained Minimal Supersymmetric SM, and more general (maybe mor...