Correlation Between Muon $g-2$ and $\mu \to e\gamma$

Abstract

While the muon $g-2$ anomaly can be successfully explained by some new physics models, most of them are severely constrained by the $\mu \to e\gamma$ bound. This tension is more transparent from the effective field theory perspective, in which the two phenomena are encoded in two very similar operators. However, with the $\mathcal{O}(1)$ Wilson coefficients, the current upper bound on $\mu \to e\gamma$ indicates a new-physics cutoff scale five orders smaller than that needed to eliminate the $(g-2{)}_{\mu }$ anomaly. By summarizing all the formulae from the one-loop contributions to the muon $g-2$ with the internal-particle spin not larger than 1, we point out two general methods to reconcile the conflict between the muon $g-2$ and $\mu \to e\gamma$: the GIM mechanism and the non-universal couplings. For the latter method, we use a simple scalar leptoquark model as an illustration.

22 pages, 4 figures, updated version accepted by PRD

References in corpus (6)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• The Muon Magnetic Moment and Supersymmetry
• Constraints on two-lepton, two quark operators
• Understanding the correlation between $(g-2{)}_{\mu }$ and $\mu \to e\gamma$ in the MSSM
• Leptoquarks decaying to a top quark and a charged lepton at hadron colliders