Effects of a chiral three-nucleon force on nucleus-nucleus scattering

TL;DR

This study examines how chiral three-nucleon forces influence nucleus-nucleus elastic scattering, revealing that they make the potential less attractive and more absorptive, which improves agreement with experimental scattering data.

Contribution

It introduces a method to incorporate chiral 3NF effects into the g-matrix folding model for nucleus-nucleus scattering, enhancing the accuracy of theoretical predictions.

Findings

3NF effects reduce the folding potential's attraction.

3NF effects increase the absorptive part of the potential.

Improved agreement with experimental scattering data.

Abstract

We investigate the effects of chiral NNLO three-nucleon force (3NF) on nucleus-nucleus elastic scattering, using a standard prescription based on the Brueckner-Hartree-Fock method and the g-matrix folding model. The g-matrix calculated in nuclear matter from the chiral N3LO two-nucleon forces (2NF) is close to that from the Bonn-B 2NF. Because the Melbourne group have already developed a practical g-matrix interaction by localizing the nonlocal g-matrix calculated from the Bonn-B 2NF, we consider the effects of chiral 3NF, in this first attempt to study the 3NF effects, by modifying the local Melbourne g-matrix according to the difference between the g-matrices of the chiral 2NF and 2NF+3NF. For nucleus-nucleus elastic scattering, the 3NF corrections make the folding potential less attractive and more absorptive. The latter novel effect is due to the enhanced tensor correlations in triplet channels. These changes reduce the differential cross section at the middle and large angles, improving the agreement with the experimental data for 16O-16O scattering at 70 MeV/nucleon and 12C-12C scattering at 85 MeV/nucleon.