Majorana parameters of the interacting boson model of nuclear structure and their implication for 0νββ decay

• Published in: Physical review. C 2021-12, Vol.104 (6)
• Main Authors: Kleemann, J., Beck, T., Friman-Gayer, U., Pietralla, N., Werner, V., Finch, S. W., Kotila, J., Krishichayan, None, Löher, B., Pai, H., Papst, O., Tornow, W., Weinert, M., Zilges, A.
• Format: Article
• Language: English
• Subjects: NUCLEAR PHYSICS AND RADIATION PHYSICS
• ISSN: 2469-9985; 2469-9993
• DOI: 10.1103/PhysRevC.104.L061302

Here, the well-known spherical-deformed-transitional nucleus and potential 0$\textit{νββ}$ emitter 150Nd and its daughter 150Sm were investigated in nuclear resonance fluorescence experiments using quasimonoenergetic, linearly polarized γ-ray beams. For both nuclei transitions from the 1+ scissors mode to the $0^+_2$ and $2^+_2$ states were observed for the first time and their respective $\textit{M}$ 1 transition strengths were determined. Through a systematic investigation, a sensitivity of these transition strengths to the three Majorana parameters of the interacting boson model-2 (IBM-2) was established. In combination with the novel experimental data, this poses strong constraints to the Majorana parameters in improved IBM-2 representations of both nuclei. A subsequent recalculation of the nuclear matrix elements (NMEs) for the 150Nd → 150Sm 0$\textit{νββ}$ decay in the IBM-2 with these improved representations results in $M^{(0νββ)}_{\text{IBM-2}}[0^+_1]$ = 3.35 for the NME for 0$\textit{νββ}$ decay into the ground state of 150Sm and $M^{(0νββ)}_{\text{IBM-2}}[0^+_2]$ = 1.30 for 0$\textit{νββ}$ decay to its $0^+_2$ state.