A1 Journal article (refereed)
Elucidating the nature of the proton radioactivity and branching ratio on the first proton emitter discovered 53mCo (2023)

Sarmiento, L. G., Roger, T., Giovinazzo, J., Brown, B. A., Blank, B., Rudolph, D., Kankainen, A., Alvarez-Pol, H., Arokia Raj, A., Ascher, P., Block, M., Caamaño-Fresco, M., Caceres, L., Canete, L., Cox, D. M., Eronen, T., Fahlander, C., Fernández-Domínguez, B., Forsberg, U., . . . Voss, A. (2023). Elucidating the nature of the proton radioactivity and branching ratio on the first proton emitter discovered 53mCo. Nature Communications, 14, Article 5961. https://doi.org/10.1038/s41467-023-39389-2

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Publication details

All authors or editorsSarmiento, Luis G.; Roger, Thomas; Giovinazzo, Jérôme; Brown, B. Alex; Blank, Bertram; Rudolph, Dirk; Kankainen, Anu; Alvarez-Pol, Héctor; Arokia Raj, Alex; Ascher, Pauline; et al.

Journal or seriesNature Communications


Publication year2023

Publication date25/09/2023


Article number5961

PublisherSpringer Nature

Publication countryUnited Kingdom

Publication languageEnglish


Publication open accessOpenly available

Publication channel open accessOpen Access channel

Publication is parallel published (JYX)https://jyx.jyu.fi/handle/123456789/89350


The observation of a weak proton-emission branch in the decay of the 3174-keV 53mCo isomeric state marked the discovery of proton radioactivity in atomic nuclei in 1970. Here we show, based on the partial half-lives and the decay energies of the possible proton-emission branches, that the exceptionally high angular momentum barriers, 𝓁p=9 and 𝓁p=7, play a key role in hindering the proton radioactivity from 53mCo, making them very challenging to observe and calculate. Indeed, experiments had to wait decades for significant advances in accelerator facilities and multi-faceted state-of-the-art decay stations to gain full access to all observables. Combining data taken with the TASISpec decay station at the Accelerator Laboratory of the University of Jyväskylä, Finland, and the ACTAR TPC device on LISE3 at GANIL, France, we measured their branching ratios as bp1 = 1.3(1)% and bp2 = 0.025(4)%. These results were compared to cutting-edge shell-model and barrier penetration calculations. This description reproduces the order of magnitude of the branching ratios and partial half-lives, despite their very small spectroscopic factors.

Keywordsnuclear physicsradioactivityprotons

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Ministry reportingYes

Reporting Year2023

JUFO rating3

Last updated on 2024-03-07 at 01:26