Ab-initio coupled-cluster calculations of ground and dipole excited states in 8He

TL;DR

This paper uses advanced coupled-cluster methods with chiral interactions to accurately compute ground and excited state properties of the halo nucleus 8He, providing benchmarks for future experiments.

Contribution

It introduces high-precision coupled-cluster calculations including three-particle three-hole excitations for 8He with chiral interactions, improving agreement with experimental data.

Findings

Ground-state energy and charge radius are consistent with experiment.

Calculated electric dipole polarizability serves as a benchmark for future measurements.

Discussed sum rules related to dipole excitations.

Abstract

We perform coupled-cluster calculations of ground- and dipole excited-state properties of the 8He halo nucleus with nucleon-nucleon and three-nucleon interactions from chiral effective field theory, both with and without explicit delta degrees of freedom. By increasing the precision in our coupled-cluster calculations via the inclusion of leading order three-particle three-hole excitations in the cluster operator, we obtain a ground-state energy and a charge radius that are consistent with experiment, albeit with a slight under-binding. We also investigate the excited states induced by the electric dipole operator and present a discussion on the Thomas-Reiche-Kuhn and cluster sum rules. Finally, we compute the electric dipole polarizability, providing a theoretical benchmark for future experimental determinations that will study this exotic nucleus.