Momentum-space approach to nuclear reaction studies: opportunities and perspectives

Abstract

The application of momentum-space three-and four-body scattering equations to the description of nuclear reactions involving systems of three and four nucleons is reviewed, and major achievements and challenges are identified. The calculations include realistic state-of-the-art interactions between nucleon pairs, together with the Coulomb interaction between protons. The effect of including three-and four-nucleon forces is discussed. Further calculations are shown involving the study of nuclear reactions where three-body degrees of freedom play a significant role. These studies involve not just an attempt to describe data in terms of a full three-body model that is solved numerically in a converged way, but also to use this exact framework to validade and test the accuracy of approximate reaction methods such as continuum discretized coupled channel (CDCC), distorted wave impulse approximation (DWIA), plane-wave impulse approximation (PWIA) and the Glauber multiple scattering approach. These comparisons are able to teach researchers under which conditions approximate methods can be used to extract important structural information about exotic nuclei. Prospects and challenges are discussed.

The quest for light multineutron systems

“…In 2018 Deltuva studied 3n [129] and 4n [130] states in the framework of AGS equations in momentum space [131]. This formalism, equivalent to FY equations, provides rigorous solutions for the three-and four-body problem and describes very accurately all the corresponding nuclear systems around the breakup thresholds [132,133,134]. An important advantage of the AGS approach with respect to previous calculations is its ability to compute the resonance position and its effect on the scattering amplitudes that could lead to observables in a scattering process, in particular the 3n → 3n and 4n → 4n transition amplitudes.…”