Correlation of Neutrinoless Double-β Decay Nuclear Matrix Element with E2 Strength

We explore the correlation of the neutrinoless double-beta decay nuclear matrix element (NME) with electric quadrupole (E2) strength in the framework of the Hamiltonian-based generator-coordinate method, which is a configuration-mixing calculation of symmetry-restored intrinsic basis states. The restoration of symmetries that are simultaneously broken in the mean-field states allows us to compute the structural and decay properties associated with wave functions characterized by good quantum numbers. Our calculations show a clear anti-correlation between the neutrinoless double-beta decay NME and the transition rate of the collective quadrupole excitation from the ground state in response to artificial changes of the quadrupole-quadrupole interaction. The anti-correlation is more remarkable in the decay from a weakly deformed parent nucleus to a more deformed grand-daughter nucleus. This interrelation may provide a way to reduce the uncertainty of the nuclear matrix element.

Automated summary

In this study, we investigate the correlation between the neutrinoless double-beta decay nuclear matrix element (NME) and electric quadrupole (E2) strength using the Hamiltonian-based generator-coordinate method. Our calculations reveal a clear anti-correlation between the NME and the transition rate of collective quadrupole excitation, particularly in the decay from a weakly deformed parent nucleus to a more deformed grand-daughter nucleus. This interrelation could potentially help reduce the uncertainty of the nuclear matrix element.