Standard Model theory:
The chart on the left shows the contributions to the value of the anomalous magnetic moment from the Standard Model particles and interactions. About 99.994% comes from contributions due to the electromagnetic force while the hadronic contributions account for only 0.006% (note the blue sliver). The right chart shows the contributions to the total uncertainty in the theoretical prediction. About 99.95% of the total error in the theoretical prediction is due the uncertainties in the hadronic corrections, while, at about 0.05% of the total error, the uncertainties in the electromagnetic and electroweak contributions are negligibly small. (QED – quantum electrodynamic; EW – electroweak; HVP – hadronic vacuum polarization; HLbL – hadronic light-by-light)