# Structure and reactions of 11Be: many-body basis for single-neutron halo

## TL;DR

This paper develops a comprehensive many-body theoretical framework to accurately describe the structure, reactions, and properties of the one-neutron halo nucleus 11Be, integrating bound and continuum states with collective core vibrations.

## Contribution

It introduces a unified approach combining empirical nuclear field theory with configuration and 3D-space methods to account for complex many-body effects in 11Be.

## Key findings

- Successfully reproduces low-lying state energies
- Accurately models resonance line shapes and cross sections
- Provides detailed characterization of many-body effects in 11Be

## Abstract

The exotic nucleus 11Be has been extensively studied and much experimental information is available on the structure of this system. Treating, within the framework of empirically renormalised nuclear field theory in both configuration and 3D-space, the mixing of bound and continuum single-particle states through the coupling to collective particle-hole (p,h) and pairing vibrations of the 10Be core, as well as Pauli principle acting not only between the particles explicitly considered and those participating in the collective states, but also between fermions involved in two-phonon virtual states it is possible, for the first time, to simultaneously and quantitatively account for the energies of the 1/2+,1/2- low-lying states, the centroid and line shape of the 5/2+ resonance, the one-nucleon stripping and pickup absolute differential cross sections involving 11Be as either target or residual nucleus, and the dipole transitions connecting the 1/2+ and 1/2- parity inverted levels as well as the charge radius, thus providing a unified and exhaustive characterisation of the many-body effects which are at the basis of this paradigmatic one-neutron halo system.