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Hadronic effects in Møller scattering at NNLO

Two-loop electroweak corrections to polarized Moller scattering are studied in two different schemes at low energies. We find the finite $Q^2$ corrections to be well under control. The hadronic and perturbative QCD corrections to the $γZ$ two-point function are incorporated through the weak mixing angle at low energies, which introduce an error of $0.08\times10^{-3}$ in the weak charge of the electron $Q^e_W$. Furthermore, by studying the scheme dependence, we obtain an estimate of the current perturbative electroweak uncertainty, $δQ^e_W\approx0.23\times10^{-3}$, which is five times smaller than the precision estimated for the MOLLER experiment $(δQ_W^e=1.1\times10^{-3})$. Future work is possible to reduce the theory error further.