A High Precision Measurement of the Neutron Electric Form Factor, GEn at High Q2

In the spring of 2006, Jefferson Lab experiment 02–013 successfully collected data to measure the neutron elastic form factor GEn at the four‐momentum transfer values Q2 = 1.2, 1.8, 2.6, and 3.5(GeV/c)2. This measurement of the quasi‐elastic semi‐exclusive 3He(e,e′n) reaction used the polarized CEBAF beam (Pb ≈ 85%) and a highly polarized 3He target (Pt ≈ 50%). Neutrons were detected in a large array of scintillators with an efficiency of 35–40%. The electrons were detected by the newly commissioned BigBite spectrometer with a solid angle of 76msr and a momentum resolution of 1%. From the transverse asymmetry of the cross section, GEn will be extracted. A statistical accuracy of ΔGEn/GEn ≈ 0.14 is expected.