The light-by-light contribution to the muon (g-2) from lightest pseudoscalar and scalar mesons within nonlocal chiral quark model

TL;DR

This paper calculates the light-by-light contribution to the muon g-2 from lightest mesons using a nonlocal chiral quark model, providing a detailed and stabilized estimate of the effect.

Contribution

It introduces a comprehensive calculation of meson contributions to muon g-2 within a nonlocal SU(3) quark model, including full off-shell kinematic dependence.

Findings

Total light-by-light contribution is (6.25 ± 0.83) x 10^{-10}.

Scalar mesons provide small positive stabilization.

Model accounts for off-shell meson and photon vertices.

Abstract

The light-by-light contribution from the lightest neutral pseudoscalar and scalar mesons to the anomalous magnetic moment of muon is calculated in the framework of the nonlocal SU(3)x SU(3) quark model. The model is based on chirally symmetric four-quark interaction of the Nambu-Jona-Lasinio type and Kobayashi-Maskawa-t`Hooft U_A(1) breaking six-quark interaction. Full kinematic dependence of vertices with off-shell mesons and photons in intermediate states in the light-by-light scattering amplitude is taken into account. The small positive contributions from the scalar mesons stabilize the total result with respect to change of model parameters and reduces to a_\mu^{LbL,PS+S}=(6.25\pm 0.83)x10^{-10}.