$^{12}$C properties with evolved chiral three-nucleon interactions

TL;DR

This paper uses ab initio No-Core Shell Model methods with chiral two- and three-nucleon interactions to study properties of carbon-12, highlighting the effects of 3N interactions and comparing different computational approaches.

Contribution

It presents a detailed analysis of $^{12}$C properties using evolved chiral interactions, benchmarking NCSM methods, and assessing the impact of 3N forces on observables.

Findings

Improved agreement with experimental data for some observables due to 3N interactions.

Benchmarking of full and importance truncated NCSM methods.

Identification of areas where current chiral Hamiltonians need refinement.

Abstract

We investigate selected static and transition properties of $^{12}$C using ab initio No-Core Shell Model (NCSM) methods with chiral two- and three-nucleon interactions. We adopt the Similarity Renormalization Group (SRG) to assist convergence including up to three-nucleon (3N) contributions. We examine the dependences of the $^{12}$C observables on the SRG evolution scale and on the model-space parameters. We obtain nearly converged low-lying excitation spectra. We compare results of the full NCSM with the Importance Truncated NCSM in large model spaces for benchmarking purposes. We highlight the effects of the chiral 3N interaction on several spectroscopic observables. The agreement of some observables with experiment is improved significantly by the inclusion of 3N interactions, e.g., the B(M1) from the first $J^\pi T = 1^+ 1$ state to the ground state. However, in some cases the agreement deteriorates, e.g., for the excitation energy of the first $1^+ 0$ state, leaving room for improved next-generation chiral Hamiltonians.