Sensitivity of one-neutron knockout of halo nuclei to their nuclear structure

Chloê Hebborn,Pierre Capel

doi:10.1088/1742-6596/1643/1/012088

Abstract

Halo nuclei are located far from stability and exhibit a very peculiar structure. Due to their very short lifetime, they are often studied through reactions. Breakup reactions are of particular interest since their cross sections are large for these loosely-bound nuclei. Inclusive measurements of breakup–also called knockout reactions-have even higher statistics. In this proceeding, we study which nuclear-structure information can be inferred from the parallel-momentum distribution of the core of one-neutron halo nuclei after the knockout of its halo neutron. In particular, we analyse the influence of the ground-state wavefunction, the presence of excited states within the halo-nucleus spectrum and resonances in the core-neutron continuum. Our analysis shows that such observables are sensitive to the tail of the ground-state wavefunction. The presence of excited state decreases the breakup strength, and this flux is transferred to the inelastic-scattering channel. This indicates a conservation of the flux within each partial wave. We also show that the parallel-momentum distributions are insensitive to the existence of resonances within the continuum, they can thus be ignored in practice. This independence of the continuum argues that the parallel-momentum distributions are ideal observables to extract very precisely the ANCs of halo nuclei.

Highlights

In the mid-eighties, the development of radioactive-ion beams has enabled the study of nuclear structure far from stability
Since the ab initio bc1asl1c/u2la=tion0.s82p9redfmic−t 1a/2s[=pec0t.r7o8s6c/o√pi0c.9facfmto−r1o/2f ]0. .9T, hwies fit this new potential to a larger single-particle asymptotic normalization constants bnlJ (SPANC) leads to a new wavefunction exhibiting a larger asymptotics and very different short-range behaviour
We rescale this wavefunction to the ab initio spectroscopic factor to obtain a wavefunction which differs strongly below 4 fm from the one normed to unity reproducing the ab initio asymptotic normalization constants CnlJ (ANC) [14]

Summary

Introduction

In the mid-eighties, the development of radioactive-ion beams has enabled the study of nuclear structure far from stability. Breakup reactions describe the dissociation of the halo from the core and reveal the cluster structure inside the nucleus [3]. Their cross sections are very large thanks to the fragile binding of the halo to the core. From a theoretical point of view, these reactions have two contributions [5]: the diffractive breakup, where both the neutron and the core survive the collision, and the stripping part, where the neutron is absorbed by the target They are measured at intermediate energies between 60-100A MeV and are usually analysed within the eikonal model, accurate at such energies [5,6,7].

Theoretical framework

Results

Conclusions