Speaker
Oliver Kirsebom
Description
We report the first detection of the second-forbidden, non-unique,
$2^+\rightarrow 0^+$, ground-state transition in the beta decay of $^{20}$F.
A low-energy, mass-separated $^{20}$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 log-ft value inferred from the observed beta yield is remarkably
large, making this the strongest second-forbidden, non-unique transition ever
measured. The result is supported by shell-model calculations and has important
implications for the final evolution of Super-AGB stars.
