Matter Radii of Light Halo Nuclei

We reexamine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using ¹¹Li, ¹¹Be, and ⁸B as examples we show that data require significantly larger matter radii than previously reported. The revised value for ¹¹Li of 3.55 fm is consistent with three-body models with significant 1s-intruder state components, which reproduce experimental ⁹Li momentum distributions following ¹¹Li breakup, but were hitherto thought to be at variance with cross section data.