Effect of Tensor Correlations on Single-particle and Collective States

TL;DR

This paper investigates how tensor correlations influence single-particle energies and collective excitations in nuclei using Skyrme Hartree-Fock and RPA models, revealing significant effects on shell structure and spin-dependent states.

Contribution

It demonstrates the impact of tensor interactions on nuclear shell structure and spin excitations without compromising other nuclear properties.

Findings

Tensor interactions explain isospin dependence of shell structure.

Coupling of Gamow-Teller and spin-quadrupole states shifts strength to higher energies.

Main GT peak shifts downward by approximately 2 MeV.

Abstract

We study the effect of tensor correlations on single-particle and collective states within Skyrme Hartree-Fock and RPA model. Firstly, We study the role of tensor interactions in Skyrme effective interaction on the spin-orbit splittings of N=82 isotones and Z=50 isotope. The isospin dependence of the shell structure is well described as the results of the tensor interactions without destroying good properties of the binding energy and the rms charge radii of the heavy nuclei. Secondly, We performed self-consistent HF+RPA calculations for charge exchange 1$^+$ states in $^{90}$Zr and $^{208}$Pb to elucidate the role of tensor interactions on spin dependent excitations. It is pointed out that Gamow-Teller(GT) states can couple strongly with the spin-quadrupole (SQ) 1$^+$ states in the high energy region above E$_x$=30 MeV due to the tensor interactions. As the result of this coupling, more than 10% of the GT strength is shifted to the energy region above 30 MeV, and the main GT peak is moved 2 MeV downward.