Description of alpha-clustering of ⁸Be nucleus states in high-precision theoretical approach

Abstract

Scrupulous theoretical study of 8Be nucleus states, both clustered and non-clustered, is performed over a wide range of excitation energies. The quantities that characterize the degree of the alpha-clustering of these states, i.e., spectroscopic factors, cluster form factors, and alpha-decay widths, are computed in the framework of the developed accurate ab initio approach. Other basic properties of the 8Be spectrum, including the binding and excitation energies and the mean values of the isospin, are calculated simultaneously. In the majority of instances, the results of the computation turn out to be in good agreement with the spectroscopic data. A number of predictions are made, and corresponding verification experiments are proposed. Prospects of the developed approach for nuclear spectroscopy are demonstrated.

Detailed study of decay properties of 7He nucleus states in ab initio approach

“…In our previous works [45][46][47], it was shown that even a not too large deviation of the calculated resonance energy from the experimental one leads to a noticeable change in the calculated value of the decay width. For this reason, the use of experimental resonance energies in calculating decay widths is preferable.…”

“…In our previous papers [45][46][47], an ab initio approach was developed. It allows one to calculate the asymptotic characteristics of the real decay of unbound and virtual splitting of bound states of nuclei namely the total and partial decay widths and the asymptotic normalization coefficients (ANCs) of certain channels, respectively.…”

“…The results of our studies presented in Refs. [46,47] give the answer yes to this question for nuclei 7 Li and 8 Be which are close to 7 He in mass, and not only for one-nucleon, but even for cluster channels.…”

Shape Mixing and Clustering in Nuclei: Probing Physics beyond the Standard Model

“…Moreover, in the recent calculations with the Daejon16 N N interaction in Ref. [20] the energy of the intruder 0 + is shown to drop to 11.71 MeV in the largest model space with Ω =15 MeV. The study also calculated the widths of the 0 + and 2 + states to be 8.86 MeV and 3.57 MeV, respectively, using NCSM combined with the resonating group method (RGM).…”

“…In addition, a recent experimental study has found a tentative evidence for a broad 0 + state at 12 MeV, prompting a need for further measurements [17]. Various earlier ab initio studies have seen intruder 0 + and 2 + states as well [18][19][20]. In particular, the extrapolations in the earlier study in Ref.…”