A Precise Measurement of the Neutron Magnetic Form Factor GMn in the Few-GeV2 Region

TL;DR

This study precisely measures the neutron magnetic form factor GMn across a wide Q2 range using quasielastic electron scattering on deuterium, employing a ratio technique and in-situ calibration for high accuracy.

Contribution

It provides the most precise measurements of GMn in the 1 to 4.8 GeV2 region, improving accuracy through innovative calibration and ratio methods.

Findings

GMn data is well described by the dipole parameterization.

High-precision GMn values were obtained across the entire Q2 range.

Multiple measurements at different energies enhanced data reliability.

Abstract

The neutron elastic magnetic form factor GMn has been extracted from quasielastic electron scattering data on deuterium with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic coverage of the measurement is continuous from Q2=1 GeV2 to 4.8 GeV2. High precision was achieved by employing a ratio technique in which many uncertainties cancel, and by a simultaneous in-situ calibration of the neutron detection efficiency, the largest correction to the data. Neutrons were detected using the CLAS electromagnetic calorimeters and the time-of-flight scintillators. Data were taken at two different electron beam energies, allowing up to four semi-independent measurements of GMn to be made at each value of Q2. The dipole parameterization is found to provide a good description of the data over the measured Q2 range.