Low-lying continuum states of drip-line Oxygen isotopes

TL;DR

This paper introduces the Continuum-Coupled Shell Model (CCSM) to study low-lying continuum states in exotic oxygen isotopes, successfully matching experimental neutron emission spectra and comparing favorably with other models.

Contribution

The paper develops a novel CCSM framework with an infinite wall and realistic interactions, providing improved insights into continuum effects in exotic nuclei.

Findings

Neutron emission spectra agree well with experimental data.

Continuum effects are significant, exceeding 1 MeV.

CCSM results are consistent with other models like the Gamow shell model.

Abstract

Low-lying continuum states of exotic oxygen isotopes are studied, by introducing the Continuum-Coupled Shell Model (CCSM) characterized by an infinite wall placed very far and by an interaction for continuum coupling constructed in a close relation to realistic shell-model interaction. Neutron emission spectra from exotic oxygen isotopes are calculated by the doorway-state approach in heavy-ion multi-nucleon transfer reactions. The results agree with experiment remarkably well, as an evidence that the continuum effects are stronger than $\sim$1 MeV, consistently with the shell evolution in exotic nuclei. The results by this CCSM doorway-state approach are compared with calculations on neutron-scattering resonance peaks made within the CCSM phase-shift approach and also with those obtained in the Gamow shell model, by taking the same interaction. Remarkable similarities in peak energies and certain differences in widths are then obtained.