Eunja Ha, Myung-Ki Cheoun
We developed the deformed quasi-particle random phase approximation (DQRPA) to describe various properties of deformed nuclei and applied to the evaluation of the Gamow-Teller (GT) transition strength distribution which can be extracted from the experiment of charge exchange reactions (CEXR). Our calculations are started with the single-particle states calculated by the deformed axially symmetric Woods-Saxon potential. Pairing correlations of nucleons, neutron-neutron and proton-proton as well as neutron-proton pairing correlations, are explicitly taken into account at the deformed Bardeen Cooper Schriffer (BCS) theory leading to the quasi-particle concept. The ground state correlations by the many-particle and many-hole mixing states are included by the deformed QRPA. In this work, we use a realistic two-body interaction given by the Brueckner G-matrix based on the Bonn potential to reduce the ambiguity on the nucleon-nucleon interactions inside nuclei. We applied our formalism to the GT transition strengths for 26Mg, 76Ge, 82Se, 90Zr, and 92Zr, and compared to available experimental data. The GT strength turns out to be sensitive on the deformation parameter. We suggest most probable deformation parameters for the nuclei by adjusting total GT strength to the experimental data and the Ikeda sum rule, which sum rule is usually thought to be satisfied more or less even under the one-body current approximation without introducing the quenching factor, if high-lying excited states are properly taken into account as in our approach. Most of the experimental GT strength data of the nuclei, in specific, on the high-lying excited states beyond one nucleon threshold are confirmed in our DQRPA by the deformation parameter determined such a way.
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http://arxiv.org/abs/1205.4561
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