Strangeness Vector and Axial-Vector Form Factors of the Nucleon

Physics Department, New Mexico State University, Las Cruces NM 88003, USA

^a e-mail: pate@nmsu.edu

Published online: 20 March 2014

Abstract

A revised global fit of electroweak ep and vp elastic scattering data has been performed, with the goal of determining the strange quark contribution to the vector and axial-vector form factors of the nucleon in the momentum-transfer range 0 < Q² < 1 GeV². The two vector (electric and magnetic) form factors G^s_E(Q²) and G^s_M(Q²) are strongly constrained by ep elastic scattering data, while the major source of information on the axial-vector form factor G^s_A(Q²) is vp scattering data. Combining the two kinds of data into a single global fit makes possible additional precision in the determination of these form factors, and provides a unique way to determine the strange quark contribution to the nucleon spin, ΔS , independently of leptonic deep-inelastic scattering. The fit makes use of data from the BNL-E734, SAMPLE, HAPPEx, G0, and PVA4 experiments; we will also compare the result of the fit with recent data from MiniBooNE, and anticipate how this fit can be improved when new data from MicroBooNE become available.