Nowadays quantum-mechanical theory allows one to reliably calculate the processes of $2p$ radioactivity (true three-body decays) and the corresponding energy and angular correlations up to distances of the order of ${10}^3$ fm. However, the precision of modern experiments has now become sufficient to indicate some deficiency of the predicted theoretical distributions. In this paper we discuss extrapolation along the classical trajectories as a method to improve the convergence of the theoretical energy and angular correlations at very large distances (of the order of atomic distances), where only long-range Coulomb forces are still operating. The precision of this approach is demonstrated using the “exactly” solvable semianalytical models with simplified three-body Hamiltonians. It is also demonstrated that for heavy $2p$ emitters, the $2p$ decay momentum distributions can be sensitive to the effect of screening by atomic electrons. We compare theoretical results with available experimental data.

• Received 17 April 2010

DOI:https://doi.org/10.1103/PhysRevC.82.014615