Anatomy of nuclear matrix elements for neutrinoless double-beta decay

TL;DR

This paper investigates the detailed nuclear physics influencing neutrinoless double-beta decay matrix elements, highlighting the importance of short-range interactions and their treatment in theoretical models.

Contribution

It provides a detailed analysis of how short-range physics affects the nuclear matrix elements within QRPA and RQRPA frameworks, and quantifies uncertainties from different correlation treatments.

Findings

Matrix elements nearly vanish beyond 2-3 fermis due to interaction competition.

Short-range physics significantly influences matrix element sensitivity.

Different treatments of short-range correlations produce quantifiable uncertainty.

Abstract

We show that, within the Quasiparticle Random Phase Approximation (QRPA) and the renormalized QRPA (RQRPA) based on the Bonn CD nucleon-nucleon interaction, the competition between the pairing and the neutron-proton particle-particle and particle-hole interactions causes contributions to the neutrinoless double-beta decay matrix element to nearly vanish at internucleon distances of more than 2 or 3 fermis. As a result, the matrix element is more sensitive to short-range/high-momentum physics than one naively expects. We analyze various ways of treating that physics and quantify the uncertainty it produces in the matrix elements, with three different treatments of short-range correlations.