Pushing the limits of hadronic many-body scattering theories: analyses of proton scattering from helium isotopes

The energy and mass regions where application of non-relativistic many nucleon based microscopic models for proton scattering from nuclei are appropriate are not well defined. Here, we use such and analyse proton scattering from various helium nuclei at 72 and 200 MeV to see how well results predict the experimental data. The structure of these nuclei are set by the evaluation of ground state properties and confirmed by the prediction of electron form factors. Then, we make predictions of the differential cross sections and spin observables of p-3,4He at 200 MeV and p-4,6,8He at 72 MeV, to ascertain whether the reaction mechanisms involved in our microscopic model are appropriate especially at energies below the 'traditional' intermediate energy range. It is shown that for proton scattering from 4He at 200 MeV, the many-body microscopic model leads to a reasonable reproduction of the experimental data when a sufficiently large shell model structure is used, but the fits deteriorate with increasing momentum transfer. It is concluded that the problems encountered in describing low energy scattering from very light nuclei is more likely due to structure considerations that ones associated with reaction mechanisms