Microscopic Description of 8Li and 8B Nuclei within a Three-Cluster Model

Abstract

The theoretical analysis of structures of the bound and resonance states in 8 Li and 8 B nuclei is performed within a three-cluster microscopic model. In the framework of this model, 8 Li and 8 B nuclei are considered as three-cluster configurations 4 + 3 + and 4 + 3 + , respectively. A distinguished peculiarity of the model is that it allows us to consider the polarizability of weakly bound nuclei such as 7 Li composed of an alpha particle and a triton or 7 Be composed of an alpha particle and 3 He. Gaussian and oscillator bases are used to expand the three-cluster wave function and to represent the many-channel Schrödinger equation in a matrix form. The main attention of the present study is paid to the effects of cluster polarization on the spectrum of bound and resonance states of 8 Li and 8 B and on the elastic and inelastic + 7 and + 7 scattering. It is shown that the cluster polarization has a great impact on parameters of the bound and resonance states in 8 Li and 8 B. For instance, it decreases the energy of resonance states by 0.7-2.0 MeV and increases their lifetime by more than three times. The roles of spin-orbital and Coulomb interactions in the formation of the spectrum of excited states in nuclei 8 Li and 8 B are studied in detail. In particular, it is found out that the Coulomb forces shift up the energy of resonance states in 8 B with respect to the position of corresponding resonance states in 8 Li and increases their widths.

Properties of 4ΛH Hypernucleus in Three-Cluster Microscopic Models

“…Here, we draw attention to the fact that the energy splitting in the 0 + and 1 + states equals 0.77 MeV for the NF potential and −2. 19 MeV for the NS one. In the former case, the splitting value may be somewhat underestimated in relation to the experiment, but it is drastically overestimated in the latter case.…”

“…The AMGOB was formulated in work [16]. It was used to describe the properties of states in the discrete and continuous spectra of 𝑝-shell nuclei [17][18][19].…”

Effects of the Coulomb interaction on parameters of resonance states in mirror three-cluster nuclei

“…These nuclei similar to nuclei 7 Li and 7 Be were studied within the AMGOB in Ref. [27]. The three-cluster configurations α + t + n and α+ 3 He+p were projected on the dominant the two-cluster channels 7 Li+n and 7 Be+p.…”

“…It was shown in Refs. [25][26][27] that the polarization of interacting clusters substantially decreases energy and width of resonance states in a compound nucleus.…”