A First Measurement of the Nucleon Axial-vector Form Factor at Q² = 1 GeV² using Polarized Electron Scattering from Protons

In electron-nucleon scattering, the axial-vector form factor (AVFF), F_A , arises due to the weak charged-current interaction. This form factor has been extensively measured in neutrino-nucleus scattering where low statistics, poor knowledge of kinematics and nuclear corrections have limited the ability to provide an accurate result. In the neutrino oscillation community, the AVFF is one of the largest contributors to the overall uncertainty in their results. An accurate, kinematically constrained measurement of the AVFF on a free proton is of clear interest to the neutrino community. It is also essential to further our understanding of the structure of the nucleon by providing a new constraint on the Generalized Parton Distributions (GPDs) and, by comparison with mature lattice QCD calculations. In this talk I will review an experiment recently submitted to Jefferson Lab that will make the first measurement of the reaction p(e, n)ν by detecting the recoil neutron using a hadron calorimeter and time-of-flight detector with 100 ps resolution. This process is 100% parity violating which, by using a longitudinally polarized electron beam, further improves the signal to background ratio. The expected result will provide the first measurement of the AVFF at Q² = 1 GeV² on a free proton. Details of the experimental setup, backgrounds and expected results will be presented.