Two neutron correlations in exotic nuclei

TL;DR

This paper investigates two-neutron correlations in exotic halo nuclei $^{11}$Li and $^6$He using a three-body model, revealing compact neutron pairing at the surface and reproducing Coulomb breakup features.

Contribution

It introduces a three-body model with density-dependent interactions to describe neutron correlations and breakup reactions in halo nuclei.

Findings

Neutrons form compact pairs at the nuclear surface.

The model reproduces the B(E1) strength distribution near the threshold.

Energy distributions of emitted neutrons match experimental observations.

Abstract

We study the correlations between two neutrons in borromian nuclei $^{11}$Li and $^6$He by using a three-body model with a density-dependent contact two-body interaction. It is shown that the two neutrons show a compact bound feature at the nuclear surface due to the mixing of single particle states of different parity. We study the Coulomb breakup cross sections of $^{11}$Li and $^6$He using the same three-body model. We show that the concentration of the B(E1) strength near the threshold can be well reproduced with this model as a typical nature of the halo nuclei. The energy distributions of two emitted neutrons from dipole excitations are also studied using the correlated wave functions of dipole excitations.