Spin dipole nuclear matrix elements for double beta decay nuclei by charge-exchange reactions

TL;DR

This paper experimentally measures spin dipole strengths in double beta-decay nuclei using charge-exchange reactions, deriving nuclear matrix elements that are crucial for understanding neutrino-less double beta decay.

Contribution

First experimental determination of SD strengths for DBD nuclei via charge-exchange reactions, linking experimental data with theoretical models for neutrino-less DBD NMEs.

Findings

SD strengths measured for the first time using (3He,t) reactions

Derived SD NMEs are consistent with quasi-particle model estimates

Results provide insights into components of neutrino-less double beta decay NMEs

Abstract

Spin dipole (SD) strengths for double beta-decay (DBD) nuclei were studied experimentally for the first time by using measured cross sections of (3He,t) charge exchange reactions (CERs). Then SD nuclear matrix elements (NMEs) for low-lying 2- states were derived from the experimental SD strengths by referring to the experimental GT (Gamow-Teller) and F (Fermi) strengths. They are consistent with the empirical SD NMEs based on the quasi-particle model with the empirical effective SD coupling constant. The CERs are used to evaluate the SD NME, which is associated with one of the major components of the neutrino-less DBD NME.