Nuclear matrix elements for Majoron emitting double-$\beta$ decay

TL;DR

This paper provides comprehensive calculations of nuclear matrix elements for Majoron-emitting neutrinoless double beta decay using IBM-2, enabling predictions of half-lives and setting limits on Majoron coupling constants based on experimental data.

Contribution

It presents the first complete IBM-2 calculations of NMEs for Majoron-emitting double beta decay for multiple spectral indices, linking theoretical predictions with experimental constraints.

Findings

Predicted half-lives for various spectral indices.

Set upper limits on Majoron-neutrino coupling constants.

Provided a framework for interpreting experimental half-life limits.

Abstract

A complete calculation of the nuclear matrix elements (NME) for Majoron emitting neutrinoless double beta decay within the framework of IBM-2 for spectral indices $n=1,3,7$ is presented. By combining the results of this calculation with previously calculated phase space factors (PSF) we give predictions for expected half-lives. By comparing with experimental limits on the half-lives we set limits on the coupling constants $\left\langle g_{ee}^{M}\right\rangle $ of all proposed Majoron-emitting models.