Vector and Axial Nucleon Form Factors: A Duality Constrained Parameterization

We present new parameterizations of vector and axial nucleon form factors. We maintain an excellent descriptions of the form factors at low momentum transfers, where the spatial structure of the nucleon is important, and use the Nachtman scaling variable ξ to relate elastic and inelastic form factors and impose quark-hadron duality constraints at high momentum transfers where the quark structure dominates. We use the new vector form factors to re-extract updated values of the axial form factor from neutrino experiments on deuterium. We obtain an updated world average value from νμd and pion electroproduction experiments of MA = 1.014±0.014 GeV/c. Our parameterizations are useful in modeling neutrino interactions at low energies (e.g. for neutrino oscillations experiments). The predictions for high momentum transfers can be tested in the next generation electron and neutrino scattering experiments. PACS. 13.40.Gp Electromagnetic form factors – 13.15.+g Neutrino interactions – 13.85.Dz Elastic scattering – 14.20.Dh Protons and neutrons – 25.30.Bf Elastic electron scattering – 25.30.Pt Neutrino scattering