Investigation of the core-halo structure of the neutron-rich nuclei 6He and 8He by intermediate-energy elastic proton scattering at high momentum transfer

The elastic proton scattering from the halo nuclei 6He and 8He was investigated in inverse kinematics at energies around 700 MeV/u with the aim to deduce the differential cross sections for the region of high momentum transfer, covering the first diffraction minimum. For this purpose, a liquid-hydrogen target was specially developed and used for the first time allowing to obtain low-background data as compared to commonly used targets made from C-H compounds. Previous data taken in the region of small momentum transfer were sensitive to the size and the peripheral shape of the total nuclear matter density distribution but not to the inner part. The present data allow for a more detailed insight in the structure of the alike core in 6,8He through a better determination of the matter density distributions. Several density distributions calculated from different microscopic models were used to derive elastic scattering cross sections which are compared with the obtained data. (author)