A1 Journal article (refereed)
Direct measurement of the mass difference of 72As−72Ge rules out 72As as a promising β-decay candidate to determine the neutrino mass (2021)

Ge, Z., Eronen, T., de Roubin, A., Nesterenko, D. A., Hukkanen, M., Beliuskina, O., de Groote, R., Geldhof, S., Gins, W., Kankainen, A., Koszorús, Á., Kotila, J., Kostensalo, J., Moore, I. D., Raggio, A., Rinta-Antila, S., Suhonen, J., Virtanen, V., Weaver, A. P., . . . Jokinen, A. (2021). Direct measurement of the mass difference of 72As−72Ge rules out 72As as a promising β-decay candidate to determine the neutrino mass. Physical Review C, 103(6), Article 065502. https://doi.org/10.1103/PhysRevC.103.065502

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Publication details

All authors or editors: Ge, Z.; Eronen, T.; de Roubin, A.; Nesterenko, D. A.; Hukkanen, M.; Beliuskina, O.; de Groote, R.; Geldhof, S.; Gins, W.; Kankainen, A.; et al.

Journal or series: Physical Review C

ISSN: 2469-9985

eISSN: 2469-9993

Publication year: 2021

Volume: 103

Issue number: 6

Article number: 065502

Publisher: American Physical Society (APS)

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1103/PhysRevC.103.065502

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/77058

Web address of parallel published publication (pre-print): https://arxiv.org/abs/2103.08729


We report the first direct determination of the ground-state to ground-state electron-capture Q value for the 72As to 72Ge decay by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The Q value was measured to be 4343.596(75) keV, which is more than a fiftyfold improvement in precision compared to the value in the most recent Atomic Mass Evaluation 2020. Furthermore, the new Q value was found to be 12.4(40) keV (3.1 σ) lower. With the significant reduction of the uncertainty of the ground-state to ground-state Q value combined with the level scheme of 72Ge from γ-ray spectroscopy, we confirm that the five potential ultralow Q-value β+ decay or electron capture transitions are energetically forbidden, thus precluding all the transitions as possible candidates for the electron neutrino mass determination. However, the discovery of small negative Q values opens up the possibility to use 72As for the study of virtual β−γ transitions.

Keywords: nuclear physics; particle physics; neutrinos; mass (physics)

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Last updated on 2021-09-08 at 13:00