Delta isobar resonance effects studied by summed isospin spin strengths and nuclear matrix elements for double and single beta decays

TL;DR

This paper investigates how the delta isobar resonance influences nuclear matrix elements in beta decays, revealing a significant quenching effect that impacts neutrino research in nuclear physics.

Contribution

It introduces a novel analysis of delta isobar resonance effects on NMEs, highlighting a quenching coefficient around 0.7 for spin isospin components.

Findings

Delta resonance causes approximately 30% quenching of NMEs.

The study emphasizes the importance of including delta effects in neutrino-related nuclear models.

Impact on neutrino detection and property studies is discussed.

Abstract

Nuclear matrix elements (NMEs) for double and single beta decays are crucial for studying neutrino properties beyond and within the standard model. The NMEs consist mainly of the spin isospin components. The delta isobar resonance, which is strongly excited by the qualk spin isospin excitation, is shown to quench the spin isospin NMEs by a coefficient around 0.7. Impact of the delta resonance on neutrino studies in nuclei is discused.