Measurement of the $2^{+}\to 0^{+}$ ground-state transition in the $\beta$ decay of ${}^{20}$F

Abstract

We report the first detection of the second-forbidden, non-unique, $2^{+}\to 0^{+}$, ground-state transition in the $\beta$ decay of ${}^{20}$F. A low-energy, mass-separated ${}^{20}{\mathrm{F}}^{+}$ beam produced at the IGISOL facility in Jyväskylä, Finland, was implanted in a thin carbon foil and the $\beta$ spectrum measured using a magnetic transporter and a plastic-scintillator detector. The $\beta$-decay branching ratio inferred from the measurement is $b_{\beta }=[0.41\pm 0.08\text{(stat)}\pm 0.07\text{(sys)}]\times 10^{-5}$ corresponding to $\log ft=10.89(11)$, making this one of the strongest second-forbidden, non-unique $\beta$ transitions ever measured. The experimental result is supported by shell-model calculations and has significant implications for the final evolution of stars that develop degenerate oxygen-neon cores. Using the new experimental data, we argue that the astrophysical electron-capture rate on ${}^{20}$Ne is now known to within better than 25% at the relevant temperatures and densities.

arXiv comment13 pages, 16 figures, 4 tables

References in corpus (10)

• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Value of the axial-vector coupling strength in $\beta$ and $\beta \beta$ decays: A review
• Improved estimate of electron capture rates on nuclei during stellar core collapse
• A sextupole ion beam guide to improve the efficiency and beam quality at IGISOL
• Thermal Runaway During the Evolution of ONeMg Cores towards Accretion-Induced Collapse
• Astrophysical weak-interaction rates for selected $A=20$ and $A=24$ nuclei
• Discovery of an Exceptionally Strong $\beta$-Decay Transition of ${}^{20}$F and Implications for the Fate of Intermediate-Mass Stars
• The Importance of Urca-process Cooling in Accreting ONe White Dwarfs
• Electron-capture Rates in ${}^{20}$Ne for a Forbidden Transition to the Ground State of ${}^{20}$F Relevant to Final Evolution of High-density O-Ne-Mg Cores
• Shell model calculation of the beta- and beta+ partial halflifes of 54Mn and other unique second forbidden beta decays

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• Correlations of r-Process Elements in Very Metal-Poor Stars as Clues to their Nucleosynthesis Sites
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