The non-resonance shake mechanism of the neutrinoless double electronic capture

TL;DR

This paper challenges the traditional view that double neutrinoless electron capture is a resonance process, showing that a non-resonance shake mechanism significantly contributes, especially as resonance defect increases, affecting candidate nuclei like 152Gd and 164Er.

Contribution

It introduces a new shake mechanism for neutrinoless double electron capture, demonstrating its dominance over the resonance process in certain nuclei.

Findings

The shake mechanism's contribution increases with resonance defect.

For nuclei like 152Gd and 164Er, the shake mechanism is predominant.

Double neutrinoless electron capture may not be a resonance process after all.

Abstract

It is generally accepted that double neutrinoless electron capture is a resonance process. The calculations of the probability of shaking with the ionization of the electron shell occurring during the transformation of 152Gd and 164Er nuclei are performed below. These nuclides have the lowest resonance defect among all known nuclei, being considered as main candidates for discovering the neutrinoless mode of the transformation. The results show predominant contribution of the new mechanism for most of the candidate nuclei. The value of this amendment rapidly increases with an increasing resonance defect. Thus, in principle, double neutrinoless electron capture appears not to be a resonance process at all.