Elastic Scattering and Reaction Cross-section of 8Li on 209Bi

C Sengupta,L.T Bezzina,E.C Simpson,K Banerjee,D.J Hinde,M.A Stoyer,M Dasgupta,K.J Cook,C Spitaleri,R.G Pizzone,L Lamia,S Romano,M La Cognata

doi:10.1051/epjconf/202022702010

Abstract

Nuclear physics in the 21st century is driven by a quest to understand the properties of ever more exotic nuclear systems. Unusual structural phenom- ena are observed to arise in light weakly bound nuclei such as 8Li. 8Li has a cluster structure core of 7Li surrounded by a loosely bound neutron which is observed to influence reaction mechanisms near the fusion barrier. Elastic scat- tering provides a vital step towards understanding more complicated reaction mechanisms. In this work, elastic scattering was measured for 8Li + 2°9Bi at energies 2% to 34% above the barrier, allowing extraction of reaction cross- sections. The systematics of the reaction cross-sections of 8Li compared to neighbouring nuclei 6,7,9,11Li are discussed.

Highlights

Experimental and technological advances in the last few decades have allowed us to explore the structure and properties of nuclei from stability up to and beyond the driplines, where nuclides become unbound
Reaction cross-sections obtained for 6,7Li + 208Pb from precise elastic scattering data measured by Keeley et al [1] at energies above the barrier were found to be similar, with a slightly larger reaction cross-section for 6Li attributed to a smaller breakup threshold (1.473 MeV) compared to that of 7Li (2.467 MeV)
On the other end of this isotopic chain, is the exotic nucleus 11Li, which has two loosely bound neutrons (S 2n = 0.369 MeV) around a relatively well-bound 9Li core. This results in a long tail in its density distribution and gives rise to very large reaction cross-sections at energies below and above its expected barrier [2, 3]. 8Li is intermediate between 7Li and 11Li and can be thought to consist of a cluster structure core of 7Li and a loosely bound neutron (S n = 2.03 MeV)

Summary

Introduction

Experimental and technological advances in the last few decades have allowed us to explore the structure and properties of nuclei from stability up to and beyond the driplines, where nuclides become unbound. Reaction cross-sections obtained for 6,7Li + 208Pb from precise elastic scattering data measured by Keeley et al [1] at energies above the barrier were found to be similar, with a slightly larger reaction cross-section for 6Li attributed to a smaller breakup threshold (1.473 MeV) compared to that of 7Li (2.467 MeV). On the other end of this isotopic chain, is the exotic nucleus 11Li, which has two loosely bound neutrons (S 2n = 0.369 MeV) around a relatively well-bound 9Li core. This results in a long tail in its density distribution and gives rise to very large reaction cross-sections at energies below and above its expected barrier [2, 3]. The reaction cross-sections obtained for 8Li will as well as be compared with the results obtained from high energy cross-section measurements, where similar root mean square (rms) nuclear radii were found for 6,7,8,9Li [5]

Experimental Setup

Elastic Scattering Angular Distribution

Reaction Cross-section

Findings

Conclusions