RADII OF HALO NUCLEI FROM CROSS-SECTION MEASUREMENTS

The root mean square matter radii of halo nuclei provide a basic measu re in constructing, constraining, and assessing theoretical models of halo structures. We consider corrections to static density (optical li mit) Glauber model calculations of reaction cross sections of such nuc lei at high energy giving careful consideration to their intrinsic few -body structure and the adiabatic nature of the halo nucleus-target in teraction. We take as important examples the loosely bound two- and th ree-body systems Be-11, He-6, Li-11, and Be-14. The contribution of th e valence particles to the calculated reaction cross sections are show n to be significantly reduced, requiring increased halo radii to repro duce experimental data. The implications of these changes for structur e models of extended two- and three-body systems are discussed.