Nonzero angular momentum pairing correlation in shell model

TL;DR

This paper introduces a simplified shell model approximation focusing on nonzero angular momentum pairing, which reduces computational complexity and aligns well with experimental spectra for certain nuclei.

Contribution

The paper proposes a nonzero angular momentum pairing shell model that simplifies calculations and matches experimental low energy spectra more efficiently than traditional models.

Findings

Successfully applied to O18 and Ni58 nuclei.

Reduces shell model dimensionality.

Shows promising agreement with experimental data.

Abstract

A simple approximation to shell model is proposed in which the low energy excitation spectra corresponds to the identical nucleons occupying the same single particle states where they preferred to form pairs for the ground states. We call this approximation as nonzero angular momentum pairing shell model. It not only reduces the dimensionality of the shell model but also matches the number of low energy levels in experimental spectra for few cases where exact shell model predicts many more states. The special focus has been done to consider the realistic interaction derived from free nucleon-nucleon scattering data to cope with the experimental spectra. The proposed approximation to shell model has been applied to calculate the energy spectra of O18 and Ni58 nuclei where only two neutrons occupy the valence states outside the core. When compared with the experimental data, the results are found to be encouraging. It is expected that results will be more pronounced if the even-even nuclei with higher number of valence nucleons are considered.