Analysis of three-nucleon forces effects in the $A=3$ system

TL;DR

This paper evaluates the impact of three-nucleon forces in nuclear systems with A=3, highlighting the need for their inclusion and proposing modifications to existing models to better match experimental data.

Contribution

It introduces modified three-nucleon force models and assesses their effectiveness in improving nuclear property predictions.

Findings

Modified models better reproduce binding energies and scattering lengths.

New parametrizations improve agreement with polarization observables.

Three-nucleon forces are essential for accurate nuclear system descriptions.

Abstract

Using modern nucleon-nucleon interactions in the description of the $A=3,4$ nuclear systems the $\chi^2$ per datum results to be much bigger than one. In particular it is not possible to reproduce the three- and four-nucleon binding energies and the $n-d$ scattering length simultaneously. This is one manifestation of the necessity of including a three-nucleon force in the nuclear Hamiltonian. In this paper we perform an analysis of some, widely used, three-nucleon force models. We analyze their capability to describe the aforementioned quantities and, to improve their description, we propose modifications in the parametrization of the models. The effects of these new parametrization are studied in some polarization observables at low energies.