JLab Measurements of the He3 Form Factors at Large Momentum Transfers

The charge and magnetic form factors, F_C and F_M, respectively, of ³He are extracted in the kinematic range 25 fm^–2 ≤ Q² ≤ 61 fm^–2 from elastic electron scattering by detecting ³He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q² = 49.3 fm^–2 and for the charge form factor at Q² = 62.0 fm^–2. Both minima are predicted to exist in the Q² range accessible by this Jefferson Lab experiment. Here, the data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.