Speaker
Description
The robustness of the proton and neutron shells for the doubly magic nucleus $^{100}$Sn has been studied in $\beta$-decay experiments, resulting in the smallest log $ft$ value for the decay of the $^{100}$Sn ground state to the $(1^+)$ state in $^{100}$In. A decay spectroscopy experiment at the RIBF has improved the statistical uncertainties on the corresponding Gamow-Teller decay strength $B_{GT}$ by a factor of ~3, due to a tenfold increase in statistics. At the same time, a sizable reduction in $B_{GT}$ compared to the previous results was observed.
However, the extraction of the $B_{GT}$ value requires an accurate knowledge of the level scheme of the daughter nucleus $^{100}$In. In comparison with large-scale shell model calculations, multiple arrangements of $\gamma$ rays in $^{100}$In are possible due to unobserved weak $\gamma$-ray branches and a limited set of $\gamma\gamma$ coincidences. Furthermore, $\beta$-decay branches to higher-lying $(1^+)$ states in $^{100}$In have not been measured. The resulting systematic uncertainty on the $B_{GT}$ value is now comparable to the statistical uncertainty.
In order to ascertain and expand on the level scheme of $^{100}$In for tests of SM and improvements in the precision on the Gamow-Teller decay properties of $^{100}$Sn, a neutron knockout experiment on $^{101,102}$In is proposed. Doppler-corrected $\gamma$-ray energies separated by as little as 40 keV at $E_\gamma \sim 100$ keV should be resolved with the HPGe array.
