Confronting the axial-vector form factor from lattice QCD with MINERvA antineutrino-proton data
Oleksandr Tomalak, Rajan Gupta, Tanmoy Bhattacharya
Abstract
We compare recent MINERvA antineutrino-hydrogen charged-current measurements to phenomenological predictions of the axial-vector form factor based on fits to all available electron scattering and deuterium bubble-chamber data and to representative lattice-QCD (LQCD) determination by the PNDME Collaboration. While there is $1\ensuremath{\sigma}--2\ensuremath{\sigma}$ agreement in the cross section with MINERvA data for each bin in ${Q}^{2}$, we identify three regions with different relevance and opportunity for LQCD predictions. For ${Q}^{2}\ensuremath{\lesssim}0.2\text{ }\text{ }{\mathrm{GeV}}^{2}$, the phenomenological extractions have large number of data points and LQCD is competitive, while MINERvA data have large errors. For $0.2\text{ }\text{ }{\mathrm{GeV}}^{2}\ensuremath{\lesssim}{Q}^{2}\ensuremath{\lesssim}1\text{ }\text{ }{\mathrm{GeV}}^{2}$, LQCD is competitive with the MINERvA determination, and both give values larger than from phenomenological extraction. For ${Q}^{2}>1\text{ }\text{ }{\mathrm{GeV}}^{2}$, the MINERvA data are the most precise. Our analysis indicates that with improving precision of MINERvA-like experiments and LQCD data, the uncertainty in the nucleon axial-vector form factor will be steadily reduced.