Muon Interactions with Fermionic Currents in Quantum Chromodynamics: A Theoretical Review of Hadronic Contributions and Lattice QCD Approaches
Abstract Muon observables provide one of the most stringent precision tests of the Standard Model. Although the muon is a lepton and therefore does not directly participate in Quantum Chromodynamics (QCD), strong-interaction effects enter through hadronic vacuum polarization and hadronic light-by-light scattering. These non-perturbative QCD contributions dominate the theoretical uncertainty in the muon anomalous magnetic moment (g−2). This review summarizes the role of fermionic quark currents in QCD, the emergence of hadronic corrections, lattice QCD methodologies, and recent theoretical developments. Particular emphasis is placed on how quark-gluon dynamics influence precision muon measurements and constrain possible physics beyond the Standard Model. Keywords: Quantum Chromodynamics, Muon, Fermions, Hadronic Vacuum Polarization, Lattice QCD, Standard Model, Muon g−2 1. Introduction Quantum Chromodynamics is the SU(3) gauge theory describing interactions among quarks and gluons....
