Vector and Axial Nucleon Form Factors:A Duality Constrained Parameterization

TL;DR

This paper introduces new parameterizations of nucleon form factors that accurately describe their behavior at low and high momentum transfers, incorporating quark-hadron duality constraints, and updates the axial form factor value from neutrino data.

Contribution

The paper develops duality-constrained parameterizations of vector and axial nucleon form factors, improving modeling across all momentum transfers and updating the axial form factor value from experimental data.

Findings

Updated axial form factor value: M_A = 1.014 +- 0.014 GeV/c^2

Effective for modeling neutrino interactions at low energies

Predictions testable in future scattering experiments

Abstract

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 xi 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 neutrino-d and pion electroproduction experiments of M_A = 1.014 +- 0.014 GeV/c2. 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.