Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-β decay

We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes Nd-150 and Sm-150 and of the nuclear matrix element that governs the neutrinoless double-beta decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-beta decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-beta decay matrix element, so that the overall octupole-induced quenching is only about 7%.