Interplay between proton-neutron pairing and deformation in self-conjugated medium mass nuclei

Danilo Gambacurta,Denis Lacroix

doi:10.1051/epjconf/201611704005

Abstract

We employ a model combining self-consistent mean-field and shell model techniques to study the competition between particle-like and proton-neutron pairing correlations in fp-shell even-even self-conjugate nuclei. Deformation effects are realistically and microscopically described. The resulting approach can give a precise description of pairing correlations and eventually treat the coexistence of different condensate formed of pairs with different total spin/ isospin. The standard BCS calculations are systematically compared with approaches including correlation effects beyond the independent quasi-particle picture. The competition between proton-neutron correlations in the isoscalar and isovector channels is also analyzed, as well as their dependence on the deformation properties.

Highlights

The effect of correlation between nucleons of different spin and isospin, is expected to be more pronounced in self-conjugate nuclei, i.e., nuclei with the same number of protons (Z) and neutrons (N)
We investigate particle-like and p-n correlations and their dependence on nuclear deformation in a framework that combines selfconsistent mean-field calculations and the diagonalization techniques for the treatment of the pairing Hamiltonian
We found that deformation plays an important role, producing a strong quenching of the pairing correlations [11]

Summary

Introduction

The effect of correlation between nucleons of different spin and isospin, is expected to be more pronounced in self-conjugate nuclei, i.e., nuclei with the same number of protons (Z) and neutrons (N). High intensity radioactive beams will offer new possibilities to study the interplay of the isoscalar (T = 0) and isovector (T = 1) pairing interaction between protons and neutrons in these nuclei. By analyzing the relative energies of the T=0 and T=1 states in even-even and odd-odd nuclei [1] and the T = 0 band in 74Rb [2], the role of isovector proton-neutron (p-n) pairing has been recently singled out in a quite clear way. Recent experiments seem to manifest the possibility to observe exotic structures of aligned pairs [3] that could be explained in terms of isoscalar p-n pairing correlations. Se for example [4]

Objectives

Methods

Conclusion