We present a comprehensive analysis of γZ interference corrections to the weak charge of the proton measured in parity-violating electron scattering, including a survey of existing models and a critical analysis of their uncertainties. Constraints from parton distributions in the deep-inelastic region, together with new data on parity-violating electron scattering in the resonance region, result in significantly smaller uncertainties on the corrections compared to previous estimates. At the kinematics of the Q weak experiment, we determine the γZ box correction to be e V γZ = (5.60 ± 0.36) × 10 −3 . The new constraints also allow precise predictions to be made for parityviolating deep-inelastic asymmetries on the deuteron.

We examine the interference γZ box corrections to parity-violating elastic electron-proton scattering in the light of the recent observation of quark-hadron duality in parity-violating deep-inelastic scattering from the deuteron, and the approximate isospin independence of duality in the electromagnetic nucleon structure functions down to Q 2 ≈ 1 GeV 2 . Assuming that a similar behavior also holds for the γZ proton structure functions, we find that duality constrains the γZ box correction to the proton's weak charge to be e V γZ = (5.4 ± 0.4) × 10 −3 at the kinematics of the Q weak experiment. Within the same model we also provide estimates of the γZ corrections for future parity-violating experiments, such as MOLLER at Jefferson Lab and MESA at Mainz.

The Q 2 -dependence of the sum of the electric and magnetic polarizabilities of the proton is calculated over the range 0 ≤ Q 2 ≤ 6 GeV 2 using the generalized Baldin sum rule. Employing a parametrization of the F1 structure function valid down to Q 2 = 0.06 GeV 2 , the polarizabilities at the real photon point are found by extrapolating the results of finite Q 2 to Q 2 = 0 GeV 2 . We determine the evolution over four-momentum transfer to be consistent with the Baldin sum rule using photoproduction data, obtaining α + β = 13.7 ± 0.7 × 10 −4 fm 3 .I.