The influence of pairing on the nuclear matrix elements of the neutrinoless double beta decays

TL;DR

This paper investigates how pairing interactions influence the nuclear matrix elements of neutrinoless double beta decay within the Interacting Shell Model, emphasizing the role of angular momentum and seniority truncations in predicting decay rates.

Contribution

It introduces a novel analysis of NME behavior based on neutron pair angular momentum and seniority, highlighting the impact of pairing interactions on decay predictions.

Findings

Low seniority approximations overestimate NME values.

Pairing interactions are crucial for accurate NME calculations.

Angular momentum analysis improves understanding of decay mechanisms.

Abstract

We study in this letter the behavior of the neutrinoless double beta decay nuclear matrix elements (NME's) in the framework of the Interacting Shell Model. We analize them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME's predicted by different nuclear structure models. In addition, it gives back the due protagonism in this process to the pairing interaction, the interaction which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, comparable to those implicit in the quasiparticle RPA in an spherical basis, tend to overestimate the values of the NME's in several decays.