We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $alpha$ to electrons. Such a particle $A$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair,
producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $Ato e^+e^-$ reaction, and set an upper limit of $alpha/alpha simeq 10^{-6}$. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.
The electric form factor of the neutron was determined from studies of the reaction He3(e,en)pp in quasi-elastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear pola
rization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2-range over which it is known, we find GEn = 0.0225 +/- 0.0017 (stat) +/- 0.0024 (syst), 0.0200 +/- 0.0023 +/- 0.0018, and 0.0142 +/- 0.0019 +/- 0.0013 for Q2 = 1.72, 2.48, and 3.41 GeV2, respectively.
