Core-excitation three-cluster model description of ^8He and ^10He

TL;DR

This paper develops a three-cluster model using Faddeev equations to describe the low-lying energy levels of helium isotopes 8He and 10He, incorporating core excitation and three-body forces.

Contribution

It introduces a novel core-excitation three-cluster model and solves Faddeev equations for 8He and 10He, including core excitation effects and subsystem coupling.

Findings

Calculated energy levels of 8He and 10He

Predicted a 1- state in 10He between 0+ and 2+ states

Demonstrated the importance of core excitation in nuclear modeling

Abstract

We introduce a new model applying to the core-nucleus and two-neutron system. The Faddeev equations of 6He-n-n and 8He-n-n systems for 8He and 10He are solved, respectively. The potential of the subsystem in the model has been determined to make a coupling both of the ground state and the excited one inside the core nucleus. By a similar mechanism the three-nucleon system is solved with the three-body force originating from an isobar excitation of the nucleon. Inputting only the information of subsystem energy levels and widths we get the coupling constants of rank 1 Yamaguchi potential between the core nucleus and neutron. We calculate the Faddeev three-cluster equations to obtain the low-lying energy levels of 8He and 10He. The 1- state of 10He, which has not been detected yet in experiments, is located in the energy level between the 0+ and 2+ states.