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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 $$\Gamma _{rad}/\Gamma _{tot}=4.2(6)\cdot 10^{-4}$$ Γ rad / Γ tot = 4.2 ( 6 ) · 10 - 4 . This finding helps to resolve the tension between recent data published in the literature.

This letter reports on the first observation of an octupole band in the neutron-deficient (N=Z+2) nucleus 110Xe. The 110Xe nuclei were produced via the 54Fe(58Ni,2n) fusion-evaporation reaction. The emitted γ rays were detected using the jurogam 3 γ-ray spectrometer, while the fusion-evaporation residues were separated with the MARA separator at the Accelerator Laboratory of the University of Jyväskylä, Finland. The experimental observation of the low-lying 3− and 5− states and inter-band E1 transitions between the ground-state band and the octupole band proves the importance of octupole correlations in this region. These new experimental data combined with theoretical calculations using the symmetry-conserving configuration-mixing method, based on a Gogny energy density functional, have been interpreted as an evidence of enhanced octupole correlations in neutron-deficient xenon isotopes.

A detailed knowledge of the decay properties of the so called Hoyle state in the 12 C nucleus ( E x = 7.654 MeV, 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 Γ rad / Γ tot = 4.4 ( 6 ) · 10 - 4 . This finding helps to resolve the tension between recent data published in the literature., (© 2024. The Author(s).)