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E08-005: Measurements of the Target Single-Spin Asymmetry Ay in the Quasi-Elastic 3He(e,e'n) Reaction
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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 Ay (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 Ay 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 GEn experiment. In the process, they will also calculate the single-spin asymmetry Ay 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 Ay experiment.
This experiment is scheduled to run in Jefferson Lab's Experiment Hall A from April 29 through May 8, 2009.