Disassembling the Nuclear Matrix Elements of the Neutrinoless double beta Decay

TL;DR

This paper dissects the nuclear matrix elements involved in neutrinoless double beta decay across several isotopes, examining various contributing factors and their effects on decay probabilities.

Contribution

It provides a detailed analysis of the nuclear matrix elements within the Interacting Shell Model, including the impact of higher order terms, finite size effects, and correlations.

Findings

Decays to first excited states are at least 25 times more suppressed than ground state transitions.

The study reveals how different contributions affect the magnitude of nuclear matrix elements.

The evolution of NMEs with maximum seniority in wave functions is characterized.

Abstract

In this article we analyze the nuclear matrix elements (NME) of the neutrinoless double beta decays of the nuclei 48-Ca, 76-Ge, 82-Se, 124-Sn, 130-Te and 136-Xe in the framework of the Interacting Shell Model (ISM). We study the relative value of the different contributions to them, such as higher order terms in the nuclear current, finite nuclear size effects and short range correlations, as well as their evolution with the maximum seniority permitted in the wave functions. We discuss also the build-up of the NME's as a function of the distance between the decaying neutrons. We calculate the decays to final 0+ first excited states and find that these decays are at least 25 times more supressed with respect to the ground state to ground state transition.