Investigation of potential ultra-low $Q$-value $\beta$-decay candidates ${}^{89}$Sr and ${}^{139}$Ba using Penning trap mass spectrometry

Abstract

Background: Ultra-low $Q$-value $\beta$-decays are interesting processes to study with potential applications to nuclear $\beta$-decay theory and neutrino physics. While a number of potential ultra-low $Q$-value $\beta$-decay candidates exist, improved mass measurements are necessary to determine which are energetically allowed. Method: Penning trap mass spectrometry was used to determine the atomic mass of ${}^{89}$Y and ${}^{139}$La, from which $\beta$-decay $Q$-values for ${}^{89}$Sr and ${}^{139}$Ba were obtained to determine if there could be an ultra-low $Q$-value decay branch in the $\beta$-decay of ${}^{89}$Sr $\to$ ${}^{89}$Y or ${}^{139}$Ba $\to$ ${}^{139}$La. Results: The ${}^{89}$Sr $\to$ ${}^{89}$Y and ${}^{139}$Ba $\to$ ${}^{139}$La $\beta$-decay $Q$-values were measured to be $Q_{\mathrm{Sr}}$ = 1502.20(0.35) keV and $Q_{\mathrm{Ba}}$ = 2308.37(68) keV. These were compared to energies of excited states in ${}^{89}$Y at 1507.4(1) keV, and in ${}^{139}$La at 2310(19) keV and 2313(1) keV to determine $Q$-values of -5.20(37) keV for the potential ultra-low $\beta$-decay branch of ${}^{89}$Sr and -1.6(19.0) keV and -4.6(1.2) keV for those of ${}^{139}$Ba. Conclusion: The potential ultra-low $Q$-value decay branch of ${}^{89}$Sr to the ${}^{89}$Y (3/2${}^{-}$, 1507.4 keV) state is energetically forbidden and has been ruled out. The potential ultra-low $Q$-value decay branch of ${}^{139}$Ba to the 2313 keV state in ${}^{139}$La with unknown J${}^{\pi }$ has also been ruled out at the 4$\sigma$ level, while more precise energy level data is needed for the ${}^{139}$La (1/2${}^{+}$, 2310 keV) state to determine if an ultra-low $Q$-value $\beta$-decay branch to this state is energetically allowed.

arXiv comment5 pages, 3 figures

References in corpus (7)

• Direct Measurement of the Mass Difference of Ho163 and Dy163 Solves the Q-Value Puzzle for the Neutrino Mass Determination
• First Direct Double-Beta Decay Q-value Measurement of 82Se in Support of Understanding the Nature of the Neutrino
• Observation of beta decay of In-115 to the first excited level of Sn-115
• Ultra-low Q values for neutrino mass measurements
• Precise measurement of energy of the first excited state of 115Sn (Eexc = 497.3 keV)
• Beta decay of 115-In to the first excited level of 115-Sn: Potential outcome for neutrino mass
• Direct determination of the ${}^{138}$La $\beta$-decay $Q$ value using Penning trap mass spectrometry

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