Direct reactions of weakly-bound nuclei within a one dimensional model

L Moschini,Am Moro,A Vitturi

doi:10.1088/1742-6596/981/1/012004

L Moschini, Am Moro + Show 1 more

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https://doi.org/10.1088/1742-6596/981/1/012004

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Abstract

A line of research has been developed to describe structure and dynamics of weakly-bound systems with one or more valence particles. To simplify the problem we are assuming particles moving in one dimension and, despite the drastic assumption, the model encompasses many characteristics observed in experiments. Within this model we can describe, for example, one- and two-particle breakup and one- and two-particle transfer processes. We concentrate here in models involving weakly-bound nuclei with just one valence particle. Exact solutions obtained by directly solving the time-dependent Schroedinger equation can be compared with the results obtained with different approximation schemes (coupled-channels formalism, continuum discretization, etc). Our goal is to investigate the limitations of the models based on approximations, and in particular to understand the role of continuum in the reaction mechanism.

Highlights

In medium-light mass region of nuclear chart the drip-lines are characterized by the presence of the so-called halo nuclei
The problem is traditionally solved in the so-called coupled-channels approach in which the wavefunction of the system is expanded in a certain basis, and the solution of the problem moves to the study of the time evolution of the expansion coefficients
By comparing the “exact” and coupled-channels results, we can check the necessary approximations which are relevant in case of weakly-bound systems

Summary

Introduction

In medium-light mass region of nuclear chart the drip-lines are characterized by the presence of the so-called halo nuclei. While in a mean-field description bound systems do not fill all bound single-particle levels and their excitation basically promotes nucleons to empty bound levels, weakly-bound systems fully occupy all available bound states and so their excitation necessarily involve the promotion to the continuum with subsequent emission For this reason the description of halo nuclei is more involved (in particular for more than two valence particles), even considering inert cores. The problem is traditionally solved in the so-called coupled-channels approach (or in its lower order approximations) in which the wavefunction of the system is expanded in a certain basis, and the solution of the problem moves to the study of the time evolution of the expansion coefficients When this scheme is applied to weakly-bound systems, one has to deal with continuum: this involves a procedure of defining, discretizing and truncating

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