Description of nucleon elastic scattering off $^6$Li with the four-body continuum-discretized coupled-channels method

Abstract

Background: Neutron reactions off lithium isotopes up to 50 MeV are important for nuclear data science, around the International Fusion Material Irradiation Facility (IFMIF) facility in particular. Purpose: We aim at constructing a semi-microscopic reaction model that describes neutron elastic scattering off $^6$Li up to 50 MeV taking the breakup channels of $^6$Li into account. Methods: We adopt the continuum-discretized coupled-channels method (CDCC) with an $\alpha+p+n$ three-body model of $^6$Li. We employ the $g$-matrix effective interaction by Jeukenne, Lejeune, and Mahaux (JLM). The renormalization factors of the real and imaginary parts of the JLM interaction are treated as free parameters. Results: The renormalization parameter of the real part of the JLM interaction is found to be constant ($=1.1$), whereas that for the imaginary part has a smooth energy dependence. The four-body CDCC calculation with these parameters well describes the angular distributions of both proton and neutron elastic scatterings as well as the neutron total cross section and proton total reaction cross section. The applicable energy range is found to be from 7 MeV to 50 MeV. Conclusions: We have constructed a reliable reaction model for describing nucleon-$^6$Li scattering between 7 MeV and 50 MeV. This model can directly be applied to inelastic scattering and break reactions for $^6$Li with the help of the complex scaling method.