We report new measurements of the parity-violating asymmetry APV in elastic scattering of 3 GeV electrons off hydrogen and He4 targets with ⟨θlab⟩≈6.0°. The He4 result is APV=(+6.40±0.23(stat)±0.12(syst))×10−6. The hydrogen result is APV=(−1.58±0.12(stat)±0.04(syst))×10−6. These results significantly improve constraints on the electric and magnetic strange form factors GsE and GsM. We extract GsE=0.002±0.014±0.007 at ⟨Q2⟩=0.077 GeV2, and GsE+0.09GsM=0.007±0.011±0.006 at ⟨Q2⟩=0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.
Available at: http://works.bepress.com/krishna_kumar/5/