“No-Spin” States and Low-Lying Structures in ¹³⁰Xe and ¹³⁶Xe

Inelastic neutron scattering on solid XeF2 and XeF2 targets was utilized to populate excited levels in 130Xe and 136Xe. When calculating nuclear matrix elements vital to the understanding of double-beta decay, it is important to have a clear understanding of the low-lying level structure of both the parent and daughter nucleus. Of particular relevance to double-beta decay searches are the assignments of 0 states. We show here that in the case of 130Xe there are several discrepancies in the adopted level structure. We found that one previous 0 candidate level (1590 keV) can be ruled out and assigned two additional candidates (2223 and 2242 keV). In 136Xe we question the previous assignment of a 0 level at 2582 keV. Excitation function and angular distribution measurements were utilized to make spin and parity assignments of levels and place new transitions.