Impact of Lorentz violation on anomalous magnetic moments of charged leptons

We address the question whether a violation of Lorentz symmetry can explain the tension between the measurement and the Standard-Model prediction of the anomalous magnetic moment of the muon, ( g − 2) μ , and whether it can significantly impact the one of the electron, ( g — 2) e . While anisotropic Lorentz-violating effects are, in general, expected to produce sidereal oscillations in observables, isotropic Lorentz violation (LV) in the charged-lepton sector could also feed into ( g — 2) e , μ . However, we find that this type of Lorentz violation, parametrised via a dim-4 field operator of the Standard-Model Extension (SME), is already strongly constrained by the absence of vacuum Čerenkov radiation and photon decay. In particular, the observations of very-high-energetic astrophysical photons at LHAASO and of high-energetic electrons (muons) by the LHC (IceCube) place the most stringent two-sided bounds on the relevant SME coefficients ∘c (e) ( ∘c (μ) ). Therefore, any explanation of the tension in ( g − 2) μ via isotropic Lorentz violation of the minimal spin-degenerate SME is excluded, and the possible size of its impact on ( g − 2) e is very limited.