Two-neutron halo nuclei in one dimension: dineutron correlation and breakup reaction

TL;DR

This paper introduces a simple one-dimensional model for two-neutron halo nuclei, demonstrating how dineutron correlations influence breakup reactions and enhance the probability of two-neutron emission.

Contribution

The study presents a novel schematic one-dimensional model capturing dineutron correlations and their effects on nuclear breakup processes.

Findings

Dineutron correlation can be realized with simple one-dimensional models.

Dineutron correlation increases the total breakup probability.

Correlated neutrons tend to be emitted in the same direction.

Abstract

We propose a simple schematic model for two-neutron halo nuclei. In this model, the two valence neutrons move in a one-dimensional mean field, interacting with each other via a density-dependent contact interaction. We first investigate the ground state properties, and demonstrate that the dineutron correlation can be realized with this simple model due to the admixture of even- and odd-parity single-particle states. We then solve the time-dependent two-particle Schr\"odinger equation under the influence of a time-dependent one-body external field, in order to discuss the effect of dineutron correlation on nuclear breakup processes. The time evolution of two-particle density shows that the dineutron correlation enhances the total breakup probability, especially for the two-neutron breakup process, in which both the valence neutrons are promoted to continuum scattering states. We find that the interaction between the two particles definitely favours a spatial correlation of the two outgoing particles, which are mainly emitted in the same direction.