A bridge to new physics: proposing new -- and reviving old -- explanations of $a_{\mu }$

Abstract

The $4.2\sigma$ tension in the combined measurement of the anomalous magnetic moment of the muon, $a_{\mu }$, and the Standard Model prediction strongly suggests the existence of beyond the Standard Model physics. Following the Standard Model Effective Field Theory approach, we study a particular topology, the \emph{bridge} diagram, which gives a chirally enhanced contribution to $a_{\mu }$. We classify all possible 2- and 3-field SM extensions that can generate this contribution and present the full $a_{\mu }$ result for them. Within our approach, we find that several 2-field fermion-scalar extensions which had been previously discarded in the literature -- when only the Yukawa-suppressed contribution was considered -- can actually be viable models to explain the observed anomaly. Furthermore, the 3-field extensions which generate the bridge diagram represent a new class of models to account for $a_{\mu }$. We explore a particular 3-field extension which, beyond explaining $a_{\mu }$, can also account for the neutral $B$-meson anomalies and the Cabibbo angle anomaly. We present the full one-loop matching for this model and a one-loop phenomenological study.

arXiv comment31 pages, 7 figures and 4 tables

References in corpus (75)

• Final Report of the Muon E821 Anomalous Magnetic Moment Measurement at BNL
• Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm
• The anomalous magnetic moment of the muon in the Standard Model
• Leading hadronic contribution to the muon magnetic moment from lattice QCD
• Test of lepton universality with $B^0\to K^{\ast 0}{\ell }^{+}{\ell }^{-}$ decays
• The muon $g-2$ and $\alpha (M_Z^2)$: a new data-based analysis
• Complete Tenth-Order QED Contribution to the Muon g-2
• Refinements in electroweak contributions to the muon anomalous magnetic moment
• Reevaluation of the hadronic vacuum polarisation contributions to the Standard Model predictions of the muon g-2 and alpha(mZ) using newest hadronic cross-section data
• Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment revisited
• The $g-2$ of charged leptons, $\alpha (M_Z^2)$ and the hyperfine splitting of muonium
• Hadronic contribution to the muon anomalous magnetic moment to next-to-next-to-leading order
• Two-pion contribution to hadronic vacuum polarization
• The electroweak contributions to (g-2)_μ after the Higgs boson mass measurement
• Remarks on higher-order hadronic corrections to the muon g-2
• Dispersion relation for hadronic light-by-light scattering: two-pion contributions
• The hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD
• Three-pion contribution to hadronic vacuum polarization
• Dispersion relation for hadronic light-by-light scattering: pion pole
• Pseudoscalar-pole contribution to the $(g_{\mu }-2)$: a rational approach
• Search for lepton-universality violation in $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Short-distance constraints for the HLbL contribution to the muon anomalous magnetic moment
• Lattice calculation of the pion transition form factor with $N_f=2+1$ Wilson quarks
• Calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment
• Effective description of general extensions of the Standard Model: the complete tree-level dictionary
• Longitudinal short-distance constraints for the hadronic light-by-light contribution to $(g-2{)}_{\mu }$ with large-$N_c$ Regge models
• Patterns of Deviation from the Standard Model
• B-decay discrepancies after Moriond 2019
• Wilson: a Python package for the running and matching of Wilson coefficients above and below the electroweak scale
• New physics explanations of $a_{\mu }$ in light of the FNAL muon $g-2$ measurement
• Emerging patterns of New Physics with and without Lepton Flavour Universal contributions
• Hadronic vacuum polarization: $(g-2{)}_{\mu }$ versus global electroweak fits
• The muon $g$-2 and $\Delta \alpha$ connection
• Hadronic vacuum polarization contribution to the anomalous magnetic moments of leptons from first principles
• Single meson contributions to the muon's anomalous magnetic moment
• On the single leptoquark solutions to the $B$-physics anomalies
• Light-by-light scattering sum rules in light of new data
• A Global Likelihood for Precision Constraints and Flavour Anomalies
• Constraints on the two-pion contribution to hadronic vacuum polarization
• The CKM unitarity problem: A trace of new physics at the TeV scale?
• The leading hadronic contribution to $(g-2{)}_{\mu }$ from lattice QCD with $N_{\mathrm{f}}=2+1$ flavours of O($a$) improved Wilson quarks
• Axial-vector exchange contribution to the hadronic light-by-light piece of the muon anomalous magnetic moment
• New Physics in $b\to s{\ell }^{+}{\ell }^{-}$ confronts new data on Lepton Universality
• Electromagnetic and strong isospin-breaking corrections to the muon $g-2$ from Lattice QCD+QED
• Hadronic-vacuum-polarization contribution to the muon's anomalous magnetic moment from four-flavor lattice QCD
• Kaon-box contribution to the anomalous magnetic moment of the muon
• Light quark vacuum polarization at the physical point and contribution to the muon $g-2$
• Scalar Meson Contributions to a_μfrom Hadronic Light-by-Light Scattering
• Combined Explanations of the $b\to s{\mu }^{+}{\mu }^{-}$ and $b\to c{\tau }^{-}\bar{\nu }$ Anomalies: a General Model Analysis
• Strong-isospin-breaking correction to the muon anomalous magnetic moment from lattice QCD at the physical point
• Beta decays as sensitive probes of lepton flavor universality
• Low-energy phenomenology of scalar leptoquarks at one-loop accuracy
• Generic Loop Effects of New Scalars and Fermions in $b\to s{\ell }^{+}{\ell }^{-}$, $(g-2{)}_{\mu }$ and a Vector-like $4^{\mathrm{th}}$ Generation
• Global Electroweak Fit and Vector-Like Leptons in Light of the Cabibbo Angle Anomaly
• Hadronic vacuum polarization contribution to the muon $g-2$ with 2+1 flavor lattice QCD on a larger than (10 fm${)}^4$ lattice at the physical point
• Electroweak limits on physics beyond the Standard Model
• 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
• Search for vector-like leptons in multilepton final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Impact of correlations between $a_{\mu }$ and ${\alpha }_{QED}$ on the EW fit
• Anthropic solution to the magnetic muon anomaly: the charged see-saw
• Effective field theory interpretation of lepton magnetic and electric dipole moments
• Minimal Models for Dark Matter and the Muon g-2 Anomaly
• Muon $g-2$ and $B$-anomalies from Dark Matter
• Search for heavy lepton resonances decaying to a $Z$ boson and a lepton in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• Cabibbo anomaly versus electroweak precision tests: An exploration of extensions of the Standard Model
• Loops and trees in generic EFTs
• On the Statistical Treatment of the Cabibbo Angle Anomaly
• Combined Constraints on First Generation Leptoquarks
• Muonic Force Behind Flavor Anomalies
• New leptons with exotic decays: collider limits and dark matter complementarity
• Simple model for large CP violation in charm decays, B-physics anomalies, muon g-2, and Dark Matter
• What is the scale of new physics behind the muon $g-2$?
• Radiative lepton mass and muon $g-2$ with suppressed lepton flavor and CP violations
• Search for exotic leptons in final states with two or three leptons and fat-jets at 13 TeV LHC

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• Minimal model for the $W$-boson mass, $(g-2{)}_{\mu }$, $h\to {\mu }^{+}{\mu }^{-}$ and quark-mixing-matrix unitarity
• Predictions for Muon Electric and Magnetic Dipole Moments from $h\to {\mu }^{+}{\mu }^{-}$ in Two-Higgs-Doublet Models with New Leptons
• The Muon Magnetic Moment and Physics Beyond the Standard Model
• The Low-Scale Seesaw Solution to the $M_W$ and $(g-2{)}_{\mu }$ Anomalies
• Effective Field Theory of Chirally-Enhanced Muon Mass and Dipole Operators
• From the EFT to the UV: the complete SMEFT one-loop dictionary
• Visible GeV ALP from TeV Vector-like Leptons
• Collider imprint of vector-like leptons in light of anomalous magnetic moment and neutrino data
• From Higgs physics to lepton flavour violation: current bounds and future prospects for vector-like lepton models