Halo Structure of Nucleus 23Al

Abstract

The recently measured reaction cross section of 23Al is analysed inthe Glauber model with an optical limit or few-body approach. It isfound that the conventional fixed core-plus-nucleon model for halonuclei is unable to explain the observed abnormally large reaction crosssection of 23Al by any selection of the halo nucleonconfigurations. The reaction cross section of 23Al can be describedwhen the core size is enlarged, although the Coulomb barrier largelyhinders the formation of a halo structure for proton-rich nuclei. Thisis consistent with the case in s-d shell neutron-rich nuclei, where anenlarged core was proposed to explain both the reaction cross sectionand longitudinal momentum distribution data.