New Results On ~8B And ~(23)O Ground State Properties

摘要

One-nucleon removal reactions at relativistic energies have been used as spectroscopic tool to obtain information about the ground state properties of ~8B and ~(23)O. Using the FRS at GSI, the longitudinal momentum distributions of the emerging fragments after breakup and the one-nucleon removal cross-sections were measured. The relative contributions of the remaining fragments (~7Be and ~(22)O) in their ground and excited states have been determined from measurements of γ rays in coincidence with the longitudinal momentum distributions. In the ~8B case, the experimental breakup data on two different targets (C and Pb) allow a determination of the weight of the ~7Be~* component in the ~8B ground state wave function as (13.3+-2.2) %. These results are discussed in the context of a theoretical three-body model. Preliminary results on ~(23)O indicate a spin and parity assignment of 1/2~+ in agreement with shell model predictions.