# LXX International conference "NUCLEUS – 2020. Nuclear physics and elementary particle physics. Nuclear physics technologies"

Oct 11 – 17, 2020
Online
Europe/Moscow timezone

## Structure of low-lying states of $^9$Be nucleus

Oct 13, 2020, 6:35 PM
1h
Online

#### Online

Poster report Section 1. Experimental and theoretical studies of the properties of atomic nuclei.

### Speaker

Ms Raushan Kabatayeva (IETP, Al-Farabi KazNU, IITU)

### Description

An application of Glauber theory of multiple scattering to calculation of differential cross sections and polarizing characteristics of particles scattering on light nuclei took an important place in research activity of E.T.Ibraeva. All calculations were carried out in the framework of reliable spectroscopic approach to nuclear reactions. Its essence is in use of nuclear models reproducing practically all spectroscopic characteristics of the nuclei under consideration. Three-particle models of $^6$Li and $^9$Be nuclei developed in MSU are related to that; as well as a multiparticle shell model for nuclei with $A =$ 6 – 14 and particle-hole shell model with $A =$ 15; a three-particle model of $^8$Li and $^9$Li nuclei and two-particle $\alpha t$-model for $^7$Li nucleus suggested in KazNU and etc. As our experience shows when realizing the spectroscopic approach, if the dominating mechanism of process is known, one can obtain not only a description of the main characteristics of the process but can also rely on the predictive character of the theory.
The particular role is for direct evidence of the halo-structure of the low-lying excited states of $^9$Be nucleus with quantum numbers $1/2^+$ and $3/2^+$ obtained by the authors lately [1]. In the framework of $\alpha \alpha n$-model of $^9$Be nucleus it was shown that the valence neutron is located with a large probability at a distance of 11 $fm$ from the center of mass of two $\alpha$-particles, at the same time this distance is several times smaller in the ground $3/2^–$ state.
In the present work the results obtained are supported by calculations of the structure of low-lying $5/2^+$ and $5/2^–$ levels. This allows concluding generally: levels of negative parity in $^9$Be nucleus, in which the valence neutron is in $p$-state, do not have a halo-structure; at the same time the low-lying levels of positive parity do have it.
Conclusions about structure of the low-lying levels of $^9$Be nucleus, obtained on the base of $\alpha \alpha n$-model, are supported with calculations of $p^9$Be-scattering: an account of halo-structure only allows reproducing experimental data on inelastic scattering on levels of positive parity [2].

1. E.T.Ibraeva et al. Inelastic $p^9$Be scattering and halo-structure of excited states of $^9$Be. Nucl. Phys. A. 933 (2015) P. 16 – 33.
2. S.Dixit et al. Structure of $^9$Be from proton scattering at 180 $MeV$. Phys. Rev. C. V. 43. No 4. (1991). 1758 – 1776.

### Primary authors

Prof. Elena Ibraeva (Institute of Nuclear Physics; IETP, Al-Farabi Kazakh National University) Prof. Marat Zhusupov (IETP, Al-Farabi Kazakh National University) Ms Raushan Kabatayeva (IETP, Al-Farabi KazNU, IITU)