Nuclear Matter Distributions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>6</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi>He</mml:mi></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>8</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi>He</mml:mi></mml:math>from Small Angle<i>p</i>-He Scattering in Inverse Kinematics at Intermediate Energy

Differential cross sections for p- ${}^{6}\mathrm{He}$ and p- ${}^{8}\mathrm{He}$ elastic scattering have been measured in inverse kinematics at small momentum transfers up to $|t|\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.05(\mathrm{GeV}/c{)}^{2}$ and projectile energies of about 700 MeV/nucleon. Nuclear matter densities deduced from the data are consistent with the concept that ${}^{6}\mathrm{He}$ and ${}^{8}\mathrm{He}$ nuclei have an $\ensuremath{\alpha}$-like core and a significant neutron skin. The rms radii of the nuclear matter distributions were determined to be ${R}_{m}$ ${(}^{6}\mathrm{He})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.30\ifmmode\pm\else\textpm\fi{}0.07\mathrm{fm}$ and ${R}_{m}$ ${(}^{8}\mathrm{He})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.45\ifmmode\pm\else\textpm\fi{}0.07\mathrm{fm}$.