Comparative study of three-nucleon force models in A = 3,4 systems

摘要

Using modern nucleon-nucleon interactions in the description of A = 3, 4 nuclei, it is not possible to reproducenboth the three- and the four-nucleon binding energies simultaneously. This is one manifestation of the necessitynof including a three-nucleon force in the nuclear Hamiltonian. In this paper we perform a comparative studynof some widely used three-nucleon force models. We analyze their capability to describe the aforementionednbinding energies as well as the n-d doublet scattering length. The correct description of these quantities cannbe considered a stringent requirement for a nuclear Hamiltonian containing two- and three-nucleon interactionnterms. As we show, this requirement is not fulfilled by several of the models available in the literature. To satisfynit, we propose modifications in the parametrization of the three-nucleon forces and we study their effects on anfew selected N-d low-energy scattering observables.