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Title Measurement of the Neutron electric form factor at Q2=0.8 2(GeV\\c)
Authors Derek Glazier
JLAB number JLAB-PHY-03-86
LANL number (None)
Other number DOE/ER/40150-4372
Document Type(s) (Thesis) 
Supported by U.S. Naval Research: No
Supported by Jefferson Lab LDRD Funding: No
A PHD thesis
Advisor(s) :
   Gunther Rosner (Glasgow)
Publication Abstract: Nucleon form factors allow a sensitive test for models of the nucleon. Recent experiments utilising polarisation observables have resulted, for the first time, in a model-independent determination of the neutron electric form factor GnE. This method employed an 80% longitudinally polarised, high intensity (10 uA) electon beam (883 MeV) that was quasi-elastically scattered off a liquid deuterium target in the reaction D (e, en)p. A neutron polarimeter was designed and installed to measure the ratio of transverse-to-longitudinal polarisation using neutron scattering asymmetries. This ratio allowed a determination of the neutron elastic form factor, GnE, free of the previous large systematic uncertainties associated with the deuterium wave function. The experiment took place in the A1 experimental hall at MAMI taking advantage of a high resolution magnetic spectrometer. A detailed investigation was carried out into the performance of the neutron polarimeter. This utilised both analysis of the experimental data and the results of a Monte-Carlo simulation. The simulation required the creation of original models for polarised neutron scattering on hydrogen and carbon. These were able to successfully describe the experimental data giving confidence that analysis of the neutron polarisation is well understood. The central work of this thesis is the analysis for a four-momentum transfer squared, Q2=0.79 (GeV/c)2, model-independent measurement of GnE. It was found GnE=0.047+-0.009(stat)+-0.002/0.001(sys). The predictions of sophisticated nucleon models were then compared to the complete set of double polarisation data. The new data point reinforced that the Soliton model [1] gives the best parameterisation for the model-independent GnE data.
Experiment Numbers: other
Group: Hall A
Document: pdf
Accepted Manuscript:
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