Estimate of the location of the neutron drip line for calcium isotopes from an exact Hamiltonian with continuum pair correlations

A C Dassie,R M Id Betan

doi:10.1103/physrevc.102.064301

Abstract

The eastern region of the calcium isotope chain of the nuclei chart is, nowadays, of great activity. The experimental assessment of the limit of stability is of interest to confirm or improve microscopic theoretical models. The goal of this work is to provide the drip line of the calcium isotopes from the exact solution of the pairing Hamiltonian which incorporates explicitly the correlations with the continuum spectrum of energy. The modified Richardson equations, which include correlations with the continuum spectrum of energy modeled by the continuum single particle level density, is used to solve the many-body system. Three models are used, two isospin independent models with core 40Ca and 48Ca, and one isospin dependent model. One and two-neutron separation energies and occupation probabilities for bound and continuum states are calculated from the solution of the Richardson equations. The one particle drip line is found at the nucleus 57Ca, while the two neutron drip line is found at the nucleus 60Ca from the isospin independent model and at 66Ca from the isospin dependent one.

Highlights

The lego-like construction of isotopes for a given atomic nucleus, sooner or later faces the particle continuum
The calcium chain is interesting because it allows the investigation for existence of doubly magic nuclei and the evolution of the charge radius [13,14,15,16,17,18,19,20]
This paper focuses on the stability limit of the calcium isotopes

Summary

Introduction

The lego-like construction of isotopes for a given atomic nucleus, sooner or later faces the particle continuum. The last observed bound Fluorine is 31F [1], while the last bound Oxygen is 24O [2,3,4,5] This simple comparison between two elements which defer only in a single proton, shows the complicated character of drip lines systems, posing a big challenge to nuclear structure models. A handful of nuclei 59Ca and 60Ca have been recently observed [11], they are the heaviest calcium isotopes discovery up to today and both were found to be bound. Their masses are not known yet, the more recent measured atomic mass is that of 57Ca [12]. Purpose: The goal of this work is to provide the drip line of the calcium isotopes from the exact solution of the pairing Hamiltonian which incorporate explicitly the correlations with the continuum spectrum of energy

Objectives

Results

Conclusion