Effects of deformation and neutron-proton pairing on the Gamow-Teller transitions for Mg-24,Mg-26 in a deformed quasiparticle random-phase approximation

초록

We investigate effects of neutron-proton (np) pairing correlations on the Gamow-Teller (GT) transition of Mg-24,Mg-26 by explicitly taking into account deformation effects. Our calculation is performed by a deformed quasiparticle random phase approximation (DQRPA) which includes the deformation at the Bardeen-Cooper-Schrieffer and RPA stage. In this paper, we include the np pairing as well as neutron-neutron (nn) and protonproton (pp) paring correlations to the DQRPA. Our new formalism is applied to the GT transition of well-known deformed Mg isotopes. The np pairing effect is found to affect more or less the GT distribution of Mg-24 and Mg-26. But the deformation effect turns out to be much larger than the np paring effect because the Fermi surfaces smear more widely by the deformation rather than the np pairing correlations. Correlations between the deformation and the np pairing effects and their ambiguities are also discussed with the comparison to experimental GT strength data by triton and He-3 beams.

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