Consistent Methods for Extracting the Proton’s Weak Charge

The final results of the Qweak collaboration were published this year (Androic, et al., Nature 557, 207 (2018)).  That work describes how the proton’s weak charge was extracted from the parity-violating asymmetry measured in ep scattering at Q²=0.0248 (GeV/c)².  Hadronic corrections were accounted for by including other parity-violating experiments in a global fit which was extrapolated to Q²=0 to obtain the proton’s weak charge. Here we describe a new fitting technique which has the advantage that the extrapolation is linear in Q². It also relies on measured parity-violating asymmetries, but uses calculated instead of fitted axial and strange form factors. The weak charge obtained in this new procedure is consistent with that obtained in the recent publication.