Exchange effects in composite-particle interaction

Bull. Russ. Acad. Sci. Phys.

2016

Self Cite

Abstracts-An approximate approach that combines the algebraic versions of the resonating group model and the orthogonality conditions model is developed for description of radiative capture reactions. The approach is applied to the mirror 3 H(α, γ) 7 Li and 3 He(α, γ) 7 Be reactions. Astrophysical S factors and branching ratios are calculated for these reactions. The nuclear interaction of the nucleons is described, using the modified Hasegawa-Nagata potential. The obtained results agree well with the experimental data, prov ing the applicability of the proposed approach to the describing radiative capture reactions and offering pros pects for its further application.

Section: Introductionmentioning

confidence: 99%

Radiative capture reactions description using the algebraic versions of the resonating group model and the orthogonality conditions model

Solovyev

Igashov

Bull. Russ. Acad. Sci. Phys.

2016

Self Cite

“…The approximation based on such simplified treatment of the exchange effects is known as the orthogonality conditions model (OCM) [3]. The same assumption done in the framework of the AVRGM leads to the algebraic version of the OCM (AVOCM) [4]. So, the main aim of the present work is to study the role of the discussed exchange effects in the radiative capture reactions 3 H(α, γ) 7 Li and 3 He(α, γ) 7 Be using the AVRGM and the AVOCM, as well as to consider a possibility of the exchange term neglect at the radiative capture description.…”

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confidence: 99%

“…All details of the model, which are necessary for the calculations, can be found in [2,6,7]. Details of the AV-OCM are presented in [4]. It should be emphasized, that in the AVOCM exchange terms connected only with the permutations of nucleons between different clusters are neglected in the matrix elements of interaction poten- tial only.…”

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confidence: 99%

Exchange Effects in the Radiative Capture Reactions³H(α, γ)⁷Li and³He(α, γ)⁷Be

Solovyev

Igashov

2016

EPJ Web of Conferences

The mirror 3 H(α, γ) 7 Li and 3 He(α, γ) 7 Be reactions have been considered using the algebraic versions of the resonating group model and of the orthogonality conditions model. Exchange effects in interaction of the colliding nuclei and influence of the corresponding exchange terms in matrix elements of the interaction potential on calculated astrophysical S-factors for the reactions have been studied.At the present time one of the most important aims of nuclear reaction theory is to build so called ab initio approaches to description of nuclear reactions, which use realistic NN-potentials and exactly account for all exchange effects caused by the antisymmetry of a wave function of nuclear system. Such approaches are in continuous progress but, nevertheless, turn out to be very complicated procedures, which are, in fact, unrealizable for sufficiently heavy colliding nuclei. Though, there are alternative approaches suitable for heavier systems. They are based on the resonating group model (RGM) [1] or its algebraic version (AVRGM) [2] with effective NN-potentials and, as above mentioned approaches, rigorously allow for the exchange effects. However, complexities rapidly grow even in such approaches at increasing system mass. Thus, a development of reliable approximations within the existing microscopic approaches is rather topical problem of nuclear reaction theory. Such approximations will allow to simplify the calculations significantly and even to make ones realizable for sufficiently complicated systems.

Nuclear clustering using a modern shell model approach

Volya

2015

Phys. Rev. C

Nuclear clustering, alpha decays, and multi-particle correlations are important components of nuclear dynamics. In this work we put forward the Cluster-Nucleon Configuration Interaction Model. We use the modern configuration-interaction approach with advanced realistic shell-model Hamiltonians in order to study clustering phenomena; the study is facilitated by the algebraic properties of many-nucleon configurations in the harmonic oscillator basis.Using translationally invariant formalism we built cluster channels that satisfy Pauli exclusion principle as well as orthogonality and normalization conditions. We formally justify the formalism and demonstrate that, within the new method, clustering strengths satisfy sum rules that are consistent with the statistical properties of nuclear reactions with composite particles. Using properly renormalized cluster form factors our approach appears to resolve long-standing problems related to absolute normalization of the alpha clustering spectroscopic factors and their behavior in sd-shell nuclei.Our methods are demonstrated in studies of α spectroscopic factors in sd-shell nuclei and in 16 O treated in p-sd shells. Comparison with experimental data supports validity of the approach.