The roles of three-nucleon force and continuum coupling in mirror symmetry breaking of oxygen mass region

TL;DR

This paper develops an ab initio Gamow shell model incorporating three-nucleon forces and continuum coupling, accurately describing mirror nuclei near driplines and elucidating their spectral properties and Thomas-Ehrman shifts.

Contribution

It introduces a self-consistent Gamow shell model with realistic interactions, including three-nucleon forces and continuum effects, for the first time applied to mirror nuclear systems.

Findings

Good agreement with experimental data on binding energies and spectra

Resonance states and continuum coupling are crucial for dripline nuclei

Three-nucleon forces and continuum effects jointly influence Thomas-Ehrman shifts

Abstract

With both three-nucleon force and continuum coupling included, we have developed a self-consistent {\it ab initio} Gamow shell model within the Gamow Hartree-Fock (GHF) basis obtained by the realistic interaction itself. With the chiral two-nucleon N$^3$LO and three-nucleon N$^2$LO interactions, the Gamow shell model has been applied to the mirror systems of $Z=8$ neutron-rich isotopes and $N=8$ proton-rich isotones, giving good agreements with data in binding energies, dripline positions and excitation spectra. The GHF calculated that the $0d_{3/2}$, $1s_{1/2}$ and $1p_{3/2}$ orbitals are resonances. The resonance states and their interplay with nonresonant continua play a crucial role in the descriptions of nuclei around driplines. Excitation spectra and Thomas-Ehrman shifts observed can be better described when both three-nucleon force and continuum coupling are considered in calculations. The three-nucleon force and continuum coupling produce a combined effect on the Thomas-Ehrman shift, e.g., for the ${1/2}^+$ resonance level of $^{19}$Na. The calculations help the understandings of related nuclear astrophysical processes.