Scientific Reports (Aug 2024)

Clarifying the radiative decay of the Hoyle state with charged-particle spectroscopy

  • D. Dell’Aquila,
  • I. Lombardo,
  • L. Redigolo,
  • M. Vigilante,
  • F. Angelini,
  • L. Baldesi,
  • S. Barlini,
  • A. Best,
  • A. Camaiani,
  • G. Casini,
  • C. Ciampi,
  • M. Cicerchia,
  • M. D’Andrea,
  • J. Diklić,
  • D. Fabris,
  • B. Gongora Servin,
  • A. Gottardo,
  • F. Gramegna,
  • G. Imbriani,
  • T. Marchi,
  • A. Massara,
  • D. Mengoni,
  • A. Ordine,
  • L. Palada,
  • G. Pasquali,
  • S. Piantelli,
  • E. Pilotto,
  • D. Rapagnani,
  • M. Sigmund,
  • A. Stefanini,
  • D. Stramaccioni,
  • D. Tagnani,
  • I. Tišma,
  • S. Valdré,
  • G. Verde,
  • N. Vukman

DOI
https://doi.org/10.1038/s41598-024-68415-6
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 6

Abstract

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Abstract A detailed knowledge of the decay properties of the so called Hoyle state in the $$^{12}$$ 12 C nucleus ( $$E_x=7.654$$ E x = 7.654 MeV, $$0^+$$ 0 + ) is required to calculate the rate at which carbon is forged in typical red-giant stars. This paper reports on a new almost background-free measurement of the radiative decay branching ratio of the Hoyle state using advanced charged particle coincidence techniques. The exploitation, for the first time in a similar experiment, of a bidimensional map of the coincidence efficiency allows to reach an unitary value and, consequently, to strongly reduce sources of systematic uncertainties. The present results suggest a value of the radiative branching ratio of $$\Gamma _{rad}/\Gamma _{tot}=4.4(6)\cdot 10^{-4}$$ Γ rad / Γ tot = 4.4 ( 6 ) · 10 - 4 . This finding helps to resolve the tension between recent data published in the literature.