Precise mass measurements of A = 133 isobars with the Canadian Penning Trap: Resolving the Qβ− anomaly at 133Te

• Published in: Physics letters. B 2024-11, Vol.858, p.139037, Article 139037
• Main Authors: Valverde, A.A., Kondev, F.G., Liu, B., Ray, D., Brodeur, M., Burdette, D.P., Callahan, N., Cannon, A., Clark, J.A., Hoff, D.E.M., Orford, R., Porter, W.S., Savard, G., Sharma, K.S., Varriano, L.
• Format: Article
• Language: English
• ISSN: 0370-2693
• DOI: 10.1016/j.physletb.2024.139037

We report precision mass measurements of 133Sb, 133g,mTe, and 133g,mI, produced at CARIBU at Argonne National Laboratory's ATLAS facility and measured using the Canadian Penning Trap mass spectrometer. These masses clarify an anomaly in the 133Te β-decay. The masses reported in the 2020 Atomic Mass Evaluation (M. Wang et al., 2021) produce Qβ−(133Te)=2920(6) keV; however, the highest-lying 133I level populated in this decay is observed at Ei=2935.83(15) keV, resulting in an anomalous Qβ−i=−16(6) keV. Our new measurements give Qβ−(Te133)=2934.8(11) keV, a factor of five more precise, yielding Qβi=−1.0(12) keV, a 3σ shift from the previous results. This resolves this anomaly, but indicates further anomalies in our understanding of the structure of this isotope.