Hadronic Light-by-light Scattering Effect on Muon g-2

TL;DR

This paper estimates the hadronic light-by-light scattering contribution to muon g-2 using effective QCD models, providing a key theoretical input that aligns with experimental uncertainties and aids in testing the Standard Model.

Contribution

It offers a new calculation of the hadronic light-by-light contribution to muon g-2 using low energy effective theories, reducing theoretical uncertainties.

Findings

Estimated contribution: -36 x 10^{-11} with ±16 x 10^{-11} uncertainty

Result compatible with upcoming experimental measurement precision

Helps clarify the Standard Model prediction for muon g-2

Abstract

The hadronic light-by-light scattering contribution to muon $g-2$ is examined using low energy effective theories of QCD, the Nambu-Jona-Lasinio model and hidden local chiral symmetry, as guides. Our result is $- 36 \times 10^{-11}$ with an uncertainty of $\pm 16 \times 10^{-11}$, which includes our best estimate of model dependence. This is within the expected measurement uncertainty of $40\times 10^{-11}$ in the forthcoming experiment at Brookhaven National Laboratory. Our result removes one of the main theoretical obstacles in verifying the existence of the weak contribution to the muon $g-2$.