SINGLE-BETA+ DECAY IN MG-26 - A COMPARISON BETWEEN THE SHELL-MODEL AND QUASI-PARTICLE RANDOM PHASE APPROXIMATION

Single-beta-decay strength distributions, for beta+ transitions in Mg-26, are calculated using effective two-body interactions in the framework of the shell model and quasiparticle random phase approximation (QRPA). It is found that the QRPA, if treated in a consistent way, yields centroids for the strength distributions and predictions for the total strength, which are in good agreement with the shell model results. The detailed structure of the strength distribution, however, is different since the shell model generates more states than the QRPA. This conclusion turns out to be independent of the effective nucleon-nucleon interaction used.