Two-proton radioactivity and three-body decay. V. Improved momentum distributions

TL;DR

This paper improves the theoretical calculation of 2p radioactivity and three-body decay distributions by using classical trajectory extrapolation, addressing discrepancies with experimental data and considering electron screening effects.

Contribution

It introduces an extrapolation method along classical trajectories to enhance the accuracy of long-distance energy and angular correlation predictions in three-body decays.

Findings

Extrapolation improves convergence of theoretical distributions at large distances.

Long-range Coulomb forces are crucial for accurate predictions.

Electron screening affects decay momentum distributions in heavy emitters.

Abstract

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 1000 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 the 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 the 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 the screening by atomic electrons. We compare theoretical results with available experimental data.