Simplified method to include the tensor contribution in α-cluster model

Tohsaki

2018

Phys. Rev. C

Self Cite

The tensor contribution can be directly incorporated in the cluster model in a simplified way. In conventional α cluster models, the contribution of the non-central interactions exactly cancels because of the antisymmetrization effect and spatial symmetry of α clusters. The mixing of breaking components of α clusters to take into account the spin-orbit and tensor effects is needed. Previously we proposed a simplified method to include the spin-orbit effect, and also for the tensor part, a simplified model to directly take into account the contribution of the tensor interaction (called SMT) was introduced; however the contribution of the tensor interaction was quite limited. Here we improve SMT, which is called iSMT. Using newly proposed iSMT, the contribution of the tensor interaction in 4 He is more than −40 MeV, four times larger than the previous version. The method is applied to four-α cluster structure of 16 O. In 16 O, the tensor contribution is also large, and this is coming from the finite size effect for the distances among α clusters with a tetrahedral configuration.

“…Previously, we have introduced SMT [24]. In SMT, we started with an α cluster with a (0s) 4 configuration and changed it for the purpose of including the tensor contribution.…”

Section: Smt and Ismtmentioning

confidence: 99%

Improved version of a simplified method for including tensor effects in cluster models

Tohsaki

2018

Phys. Rev. C

Self Cite

“…The adopted d values in Ref. [11] were 0, 0.7, 1.4, 2.1, • • • 7.0 fm (11 Slater determinants in total). However, using this previous version of SMT, the contribution of the tensor interaction was rather limited, about −10 MeV in the α cluster.…”

Section: Tensor Interactionmentioning

confidence: 99%

“…This second order effect of the tensor interaction is more difficult to be treated in the cluster model, and we need an additional framework; we have proposed a simplified model to directly take into account the contribution of the tensor interaction (SMT) [11]. The tensor contribution was estimated in 4 He, 8 Be, and 12 C, and the relation to the clustering was quantitatively discussed.…”

Section: Introductionmentioning

confidence: 99%

Exotic Clustering and Competition with the Shell Structure in Light Neutron-rich Nuclei

Proceedings of the Ito International Research Center Symposium "Perspectives of the Physics of Nuclear Structure"

2018

Nuclear systems have quite characteristic features that non-central interactions play a crucial role. The spin-orbit interaction is quite important in explaining the observed magic numbers, and the j j-coupling shell model is based on this picture. Also, the tensor interaction makes 4 He nucleus strongly bound as a subunit of nuclear structure called α cluster. Our goal is to pave the way to generally describe the nuclear structure, including shell and cluster structures simultaneously. However, in most of the traditional cluster models, the spin-orbit and tensor interactions do not contribute inside α clusters and also between α clusters because of the antisymmetrization effect and spatial symmetry of α cluster. Therefore for the general description of the nuclear structure, we extend the model space of cluster models to the shell model side and include the contribution of non-central interactions. For the spin-orbit interaction, we proposed the antisymmetrized quasi-cluster model (AQCM), which allows smooth transition of α cluster model wave function to j j-coupling shell model one. We apply it to 12 C and 16 O. By utilizing Tohsaki interaction, which is phenomenological but has finite-range three-body interaction terms, the consistent understanding of these nuclei can be achieved, which has been a long standing problem of conventional cluster model. Using AQCM, we also discuss the anomalously large radius observed in 24 O, which is located at the dripline of Oxygen isotopes. For the tensor interaction, previously we proposed a simplified model to directly take into account the contribution of the tensor interaction (SMT); however the contribution of the tensor interaction was quite limited. Here we improve SMT, which is called iSMT. Using newly proposed iSMT, the contribution of the tensor interaction in 4 He is more than −40 MeV, four times larger than the previous version. In 16 O, the tensor contribution is also large, and this is coming from the finite size effect for the distances among α clusters with a tetrahedral configuration.

“…The use of more realistic interactions could be one of the key points to overcoming the difficulty we have encountered in the present study. The implementation of more elaborate interactions in the cluster model is now in progress [30]. support.…”

Section: Energy (Mev)mentioning

confidence: 99%

Systematic analyses of thet+tclustering effect in He isotopes

Aoyama

2006

Phys. Rev. C

Self Cite

A systematic study on the ground-state structure of He isotopes (including 10 He) is presented through a new method developed on the basis of antisymmetrized molecular dynamics (AMD), the generator coordinate method (GCM), and the stochastic variational method (SVM). In this approach, variational calculations are carried out by means of the GCM with the AMD wave functions produced by means of the SVM. A role of the t+t cluster component is examined with the present method, allowing the wider configuration space containing simultaneously the "t+t+valence neutrons" structure and " 4 He+valence neutrons" structure.