Reactions with a 10Be beam to study the one-neutron halo nucleus 11Be

TL;DR

This paper investigates the structure of the one-neutron halo nucleus 11Be using reactions with a 10Be beam, aiming to resolve longstanding discrepancies in spectroscopic factor measurements through experimental data and theoretical calculations.

Contribution

The study provides a consistent analysis of reaction channels and highlights the importance of dynamic core excitation effects in interpreting experimental data for 11Be.

Findings

Dynamic core excitation reduces differential cross sections at higher energies.

Experimental data at multiple energies helps clarify the spectroscopic factor discrepancies.

Further high-energy measurements are needed to fully understand core excitation effects.

Abstract

Halo nuclei are excellent examples of few-body systems consisting of a core and weakly-bound halo nucleons. Where there is only one nucleon in the halo, as in 11Be, the many-body problem can be reduced to a two-body problem. The contribution of the 1s1/2 orbital to the ground state configuration in 11Be, characterized by the spectroscopic factor, S, has been extracted from direct reaction data by many groups over the past five decades with discrepant results. An experiment was performed at the Holifield Radioactive Ion Beam Facility using a 10Be primary beam at four different energies with the goal of resolving the discrepancy through a consistent analysis of elastic, inelastic, and transfer channels. Faddeev-type calculations, released after the publication of the experimental results, show that dynamic core excitation in the transfer process can lead to reduced differential cross sections at higher beam energies. This reduction would lead to the extraction of decreasing values of S with increasing beam energy. A 10Be(d,p) measurement at Ed greater than 25 MeV is necessary to investigate the effects of core excitation in the reaction.