Nuclear matter distributions in the 6He and 8He nuclei from differential cross sections for small-angle proton elastic scattering at intermediate energy

A Glauber based analysis of the experimental cross sections for small-angle elastic p(6,8)He scattering at 0.7 GeV has been performed. The radii and radial shape of the He-6 and He-8 nuclei have been determined using phenomenological nuclear-density distributions with two free parameters. The deduced shapes of the He-6 and He-8 nuclear matter radial distributions conform with the concept that both nuclei consist of an alpha-particle core and a significant neutron halo. The accuracy of the theoretical analysis of the elastic-scattering cross-section data is discussed, and possible sources of systematic uncertainty related to some basic limitations in the applied method are outlined. The experimental p He-6,He-8 elastic-scattering cross sections have also been utilized for probing the matter density distributions resulting from various nuclear microscopic models. Besides, the sensitivity of the total p He-6,He-8 reaction cross sections to the size of the 6He and 8He nuclei has been considered. (C) 2002 Elsevier Science B.V. All rights reserved.