Strangeness contribution to the vector and axial form factors of the nucleon

TL;DR

This paper combines data from electron and neutrino scattering experiments to simultaneously determine the strange vector and axial form factors of the nucleon across a range of momentum transfers, providing new insights into nucleon structure.

Contribution

It presents the first simultaneous extraction of the strange vector and axial form factors of the nucleon using combined parity-violating electron and neutrino scattering data.

Findings

Determined $G_E^s$, $G_M^s$, and $G_A^s$ over $0.45<Q^2<1.0$ GeV$^2$

Established relationships between form factors from different scattering data

Provided constraints on the strange contributions to nucleon structure

Abstract

The strangeness contribution to the vector and axial form factors of the nucleon is presented for momentum transfers in the range $0.45<Q^2<1.0$ GeV$^2$. The results are obtained via a combined analysis of forward-scattering parity-violating elastic $\vec{e}p$ asymmetry data from the $G^0$ and HAPPEx experiments at Jefferson Lab, and elastic $\nu p$ and $\bar{\nu} p$ scattering data from Experiment 734 at Brookhaven National Laboratory. The parity-violating asymmetries measured in elastic $\vec{e}p$ scattering at forward angles establish a relationship between the strange vector form factors $G_E^s$ and $G_M^s$, with little sensitivity to the strange axial form factor $G_A^s$. On the other hand, elastic neutrino scattering at low $Q^2$ is dominated by the axial form factor, with still some significant sensitivity to the vector form factors as well. The combination of the two data sets allows the simultaneous extraction of $G_E^s$, $G_M^s$, and $G_A^s$ over a significant range of $Q^2$ for the very first time.