Precise Mass Measurements of $A=133$ Isobars with the Canadian Penning Trap: Resolving the $Q_{\beta^-}$ anomaly at $^{133}$Te

Author:

A. A. Valverde, F. G. Kondev, B. Liu, D. Ray, M. Brodeur, D. P. Burdette, N. Callahan, A. Cannon, J. A. Clark, D. E. M. Hoff, R. Orford, W. S. Porter, K. S. Sharma, L. Varriano

Keyword:

Nuclear Experiment, Nuclear Experiment (nucl-ex)

journal:

date:

2023-12-12 00:00:00

Abstract

We report precision mass measurements of $^{133}$Sb, $^{133g,m}$Te, and $^{133g,m}$I, 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 $^{133}$Te $\beta$-decay. The masses reported in the 2020 Atomic Mass Evaluation (W.J. Huang et al., 2021) produce $Q_{\beta^-}(^{133}$Te)=2920(6) keV; however, the highest-lying $^{133}$I level populated in this decay is observed at $E_i=2935.83(15)$ keV (H.G. Hicks et al., 1983), resulting in an anomalous $Q_{\beta^{-}}^{i}=-16(6)$~keV. Our new measurements give $Q_{\beta^-}(^{133}\text{Te})=2934.8(11)$ keV, a factor of five more precise, yielding $Q{_\beta^i}=-1.0(12)$~keV, a 3$\sigma$ shift from the previous results. This resolves the anomaly and indicates the possibility of an ultralow $Q$-value $\beta$ decay in this system.

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