J. Gerl

Experimental evidence for the 8B ground state configuration

Abstract The 7Be fragments produced in one-proton removal from relativistic 8B nuclei of 936xa0MeV/nucleon in a carbon target have been detected in coincidence withxa0γ rays emitted by these fragments at the reaction target. It is found that 13±3% of the 7Be fragments are released in the 429xa0keV excited state, 7Be∗, which gives direct experimental information on the ground state configuration ofxa08B. The longitudinal momentum distributions (p∥) of the 7Be fragments have been measured, both inclusively and in coincidence with de-excitation γ-rays from 7Be∗. The widths and cross sections of the respective p∥ distributions are compared with calculations in a three-body cluster model.

Nuclear and Coulomb breakup of 8B

Abstract One-proton removal reactions of 936xa0MeV/u 8 B have been studied with carbon and lead as breakup targets. Using the FRS at GSI, the longitudinal momentum distributions of the 7 Be fragments and the one-proton removal cross section of 8 B were measured. The relative contributions of the breakup channels leading to 7 Be in its ground state and excited state at 429xa0keV ( 7 Be ∗ ) have been determined from measurements of γ rays in coincidence with the fragments from the one-proton removal reaction. The experimental breakup data are discussed in the context of a theoretical ( α+ 3 He + p ) three-body model. The combined data from the two targets allow a determination of the weight of the 7 Be ∗ component in the 8 B ground state wave function as (13.3±2.2%)

New Results On 8B And 23O Ground State Properties

One‐nucleon removal reactions at relativistic energies have been used as spectroscopic tool to obtain information about the ground state properties of 8B and 23O. 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 22O) 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 23O indicate a spin and parity assignment of 1/2+ in agreement with shell model predictions.