Nature Communications (Sep 2023)

Elucidating the nature of the proton radioactivity and branching ratio on the first proton emitter discovered 53mCo

  • Luis G. Sarmiento,
  • Thomas Roger,
  • Jérôme Giovinazzo,
  • B. Alex Brown,
  • Bertram Blank,
  • Dirk Rudolph,
  • Anu Kankainen,
  • Héctor Alvarez-Pol,
  • Alex Arokia Raj,
  • Pauline Ascher,
  • Michael Block,
  • Manuel Caamaño-Fresco,
  • Lucia Caceres,
  • Laetitia Canete,
  • Daniel M. Cox,
  • Tommi Eronen,
  • Claes Fahlander,
  • Beatriz Fernández-Domínguez,
  • Ulrika Forsberg,
  • Juan Lois-Fuentes,
  • Mathias Gerbaux,
  • Jürgen Gerl,
  • Pavel Golubev,
  • Stéphane Grévy,
  • Gwen F. Grinyer,
  • Tobias Habermann,
  • Jani Hakala,
  • Ari Jokinen,
  • Omar Kamalou,
  • Ivan Kojouharov,
  • Veli S. Kolhinen,
  • Jukka Koponen,
  • Nikolaus Kurz,
  • Nataša Lalović,
  • Christian Lorenz,
  • Benoit Mauss,
  • Alice Mentana,
  • Iain D. Moore,
  • Aurora Ortega Moral,
  • Julien Pancin,
  • Philippos Papadakis,
  • Jérôme Pibernat,
  • Julien Piot,
  • Ilkka Pohjalainen,
  • Juuso Reinikainen,
  • Sami Rinta-Antila,
  • Henning Schaffner,
  • Olivier Sorlin,
  • Christelle Stodel,
  • Jean-Charles Thomas,
  • Maud Versteegen,
  • Annika Voss

DOI
https://doi.org/10.1038/s41467-023-39389-2
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 7

Abstract

Read online

Abstract 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, $${{{{{{\mathcal{l}}}}}}}_{{{{{{\rm{p}}}}}}}=9$$ l p = 9 and $${{{{{{\mathcal{l}}}}}}}_{{{{{{\rm{p}}}}}}}=7$$ l p = 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.