Shell Model Two Body Matrix Elements Calculations for the Neutrinoless Double Beta Decay of 48Ca

In this paper we present two Shell Model approaches for computing the two-body matrix elements involved in the neutrinoless double beta decay of 48Ca. One of the methods involves integration of the radial part over the momentum space, while the other only requires computations in the coordinate space. This has an influence in the complexity of the numerical approach and the necessary computation time. We will explain how this reflects into the obtained results, pointing out the advantages and the limitations of each method.