Nuclear matter distributions in He-6 and He-8 from small angle p-He scattering in inverse kinematics at intermediate energy

Differential cross sections for p-He-6 and p-He-8 elastic scattering have been measured in inverse kinematics at small momentum transfers up to \t\ = 0.05 (GeV/c)(2) and projectile energies of about 700 MeV/nucleon. Nuclear matter densities deduced from the data are consistent with the concept that He-6 and He-8 nuclei have an alpha-like core and a significant neutron skin. The ms radii of the nuclear matter distributions were determined to be R(m) (He-6) = 2.30 +/- 0.07 fm and R(m) (He-8) = 2.45 +/- 0.07 fm.