Application of the Lagrange-mesh method in continuum-discretized coupled-channel calculations

We apply the Lagrange-mesh method to discretize continuum states of weakly bound nuclei for continuum-discretized coupled-channel (CDCC) calculations of three-body breakup reactions. This discretization method is compared with the bin method, which is regarded as the standard continuum discretization method, for the d and Li-6 induced reactions. An improved Numerov algorithm is used to solve the coupled channels equations, which permits a fast integration of equations and a convenient treatment of the closed channels. A new CDCC model code named CDCC-R is developed. In all cases, the combination of the Lagrange-mesh method and the Numerov algorithm shows high efficiency and accuracy for the CDCC calculations of the elastic scattering and breakup reactions. Especially, various numerical and physical aspects are discussed for Li-6 induced reactions. The coupling effects of the continuum states with high orbital angular momentum and closed channels are discussed. Moderate effects are found in the calculations for elastic scattering and breakup reaction when F- and G-wave continuum states are included in CDCC model space for Li-6 induced reactions at the incident energies well above the Coulomb barrier. The closed channel effect is found to be indispensable for Li-6 breakup reaction calculation when the incident energy is around the Coulomb barrier.

Automated summary

In this study, the Lagrange-mesh method was employed to discretize the continuum states of weakly bound nuclei for three-body breakup reactions. The combination of this discretization method and the improved Numerov algorithm showed high efficiency and accuracy in the CDCC calculations.