What is the scale of new physics behind the muon $g-2$?

Abstract

We study the constraints imposed by perturbative unitarity on the new physics interpretation of the muon $g-2$ anomaly. Within a Standard Model Effective Field Theory (SMEFT) approach, we find that scattering amplitudes sourced by effective operators saturate perturbative unitarity at about 1 PeV. This corresponds to the highest energy scale that needs to be probed in order to resolve the new physics origin of the muon $g-2$ anomaly. On the other hand, simplified models (e.g.~scalar-fermion Yukawa theories) in which renormalizable couplings are pushed to the boundary of perturbativity still imply new on-shell states below 200 TeV. We finally suggest that the highest new physics scale responsible for the anomalous effect can be reached in non-renormalizable models at the PeV scale.

16 pages, 4 figures

References in corpus (6)

• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• What is the scale of new physics behind the $B$-flavour anomalies?
• Consequences of chirally enhanced explanations of $(g-2{)}_{\mu }$ for $h\to \mu \mu$ and $Z\to \mu \mu$
• Expectations for the muon g-2 in simplified models with dark matter
• Massive vectors and loop observables: the $g-2$ case
• Interplay of New Physics Effects in $(g-2{)}_{\ell }$ and $h\to {\ell }^{+}{\ell }^{-}$ -- Lessons from SMEFT

Cited by in corpus (16)

• Stellar Evolution confronts Axion Models
• Global Fit of Modified Quark Couplings to EW Gauge Bosons and Vector-Like Quarks in Light of the Cabibbo Angle Anomaly
• Searching for axion forces with precision precession in storage rings
• A bridge to new physics: proposing new -- and reviving old -- explanations of $a_{\mu }$
• Width effects of broad new resonances in loop observables and application to $(g-2{)}_{\mu }$
• Indirect constraints on lepton-flavour-violating quarkonium decays
• The Ellipse of Muon Dipole Moments
• Flavour alignment of New Physics in light of the $(g-2{)}_{\mu }$ anomaly
• The Muon Magnetic Moment and Physics Beyond the Standard Model
• High-energy frontier of the muon g-2 at a muon collider
• Multi Higgs Boson Signals of a Modified Muon Yukawa Coupling at a Muon Collider
• From the EFT to the UV: the complete SMEFT one-loop dictionary
• Two-Higgs Doublet Model Effective Field Theory
• Implications of the muon anomalous magnetic moment for the LHC and MUonE
• Perturbative unitarity constraints on generic Yukawa interactions
• Positivity and partial wave unitarity bounds on ALP theories via amplitude methods