Double Polarization Asymmetry Measurement of the Electric Form Factor of the Neutron at $Q^2$=1.16 GeV$^2$ Using the Semi-Exclusive Reaction $^3\vec{\textrm{He}}(\vec{e},e'n)pp$
ORAL
Abstract
The space-like electric form factor of the neutron has been extracted at $Q^2=1.16$ GeV$^2$ via a beam-target helicity asymmetry measurement using the semi-exclusive reaction $^3\vec{\textrm{He}}(\vec{e},e'n)pp$. The Jefferson Lab Hall A experiment E02-013 ran in 2006 utilizing the 6 GeV CEBAF for its high-duty, longitudinally polarized electron beam. The double-arm coincidence experiment detected the quasielastically scattered electrons in a large angular and momentum acceptance spectrometer referred to as BigBite. The recoiling nucleons were detected in a large neutron detector, built out of planes of scintillator arrays interlaced with iron and lead plates to increase the probability of inducing a hadronic shower. The polarized $^3$He target used the novel technique of hybrid spin-exchange optical pumping, resulting in a 10 atm target that could sustain polarizations greater than 50$\%$ at a beam current of 8 $\mu$A. Presented will be the current analysis and a preliminary result for $G_E^n$ at $Q^2$=1.16 GeV$^2$.
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Authors
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Richard Obrecht
Univ of Connecticut - Storrs