The radiative width of the Hoyle state from $\gamma$-ray spectroscopy

Abstract

The cascading 3.21 MeV and 4.44 MeV electric quadrupole transitions have been observed from the Hoyle state at 7.65 MeV excitation energy in ${}^{12}$C, excited by the ${}^{12}$C(p,p${}^{\prime }$) reaction at 10.7 MeV proton energy. From the proton-$\gamma$-$\gamma$ triple coincidence data, a value of ${\Gamma }_{\mathrm{rad}}/\Gamma =6.2(6)\times 10^{-4}$ was obtained for the radiative branching ratio. Using our results, together with ${\Gamma }_{\pi }^{E0}/\Gamma$ from Eriksen et al., Phys. Rev. C 102, 024320 and the currently adopted ${\Gamma }_{\pi }(E0)$ values, the radiative width of the Hoyle state is determined as ${\Gamma }_{\mathrm{rad}}=5.1(6)\times 10^{-3}$ eV. This value is about 34% higher than the currently adopted value and will impact on models of stellar evolution and nucleosynthesis.

6 pages, 6 figures

References in corpus (5)

• The SiRi Particle-Telescope System
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• On the Sensitivity of Massive Star Nucleosynthesis and Evolution to Solar Abundances and to Uncertainties in Helium Burning Reaction Rates
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• Assessing stellar yields in Galaxy chemical evolution: observational stellar abundance patterns
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• Precise measurement of the $\gamma$-decay probability of the Hoyle state with a new triple coincidence-detection method