The study of the three-nucleon system is one of the most fundamental problems that remain in nuclear physics. The theoretical description of the two-nucleon system is the source for our understanding of the nuclear forces acting between two nucleons, which are the basis for the construction of nuclear physics as a whole. However, our understanding of multi-nucleon systems requires the inclusion of explicit three-nucleon interactions. These forces can be determined from the theoretical and experimental studies of the three- and more-nucleon systems. The experimental studies produce measurements that are to be made with minimized systematic and statistical errors to produce a reliable set of three-nucleon observables. Our current efforts seek to measure the nd breakup cross sections in configurations where current calculations and previous data vastly disagree. In order to interpret the data in relation to theoretical calculations, computations must be made to relate ideal measurement conditions to the real apparatus. The experimental group is developing these codes to simulate the experiment, and then using this expertise to apply similar particle interaction code packages to new nuclear physics experiments, specifically to a newly proposed neutrino experiment.
The theoretical studies provide calculations developed to predict and reproduce observables in three-nucleon systems with sufficient accuracy. For the continuum spectrum only three- and four-nucleon systems admit rigorous and practically feasible treatment. The most accurate approach from a mathematical point of view is to study both neutron-deuteron (nd) and proton-deuteron (pd) systems using the method of the Faddeev equations. In the case of the Faddeev equations in configuration space we can use the same computational methods and computer codes used for nd scattering to take into account the Coulomb interaction to consider pd scattering.