Quasi-Elastic Family

E08-005

In the last decade, a distinct difference was found between the neutron electric form factors extracted at low Q² using polarized deuteron vs. polarized ³He. This discrepancy was resolved by using Faddeev calculations of ³He to make the extraction. One experiment that clearly showed that the Fadeev calculations were correctly describing ³He was the measurement of a large A_y (e,e'n) asymmetry at a Q² of 0.2 [GeV/c]²; an asymmetry which in PWIA is exactly zero and which other calculations had predicted would be small. We propose to make the first measurement of this asymetry at large Q2 of 0.75 [GeV/c]² and 1.0 [GeV/c]² where the A_y asymmetry is again expected to be small. Any non-zero result is an indication of effects behond simple IA and will test models used to extract neutron form factors from ³He at large Q². Thought state of the art clculations are not yet available for this observabe, several theory groups are currently active in calculation the ³He→(e→,e'n)X reaction for the recent Hall A G_Eⁿ experiment. In the process, they will also calculate the single-spin asymmetry A_y in the ³He^↑(e,e'n) reaction and have explicitly stated that this observable will serve as a sensitive test of their models (i.e., testing the validity of the use of the models to extract the neutron form factors at high Q²). This measurement is an extension of the approved and scheduled inclusive A_y experiment.

This experiment is scheduled to run in Jefferson Lab's Experiment Hall A from April 29 through May 8, 2009.

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Web Site Maintained by Elena Long (ellie@jlab.org)
Last Updated 03/09/09