Decay spectroscopy of $N < Z$ nuclei around $^{100}$Sn

Many interesting topics in both nuclear structure and nuclear astrophysics converge on the doubly-magic nucleus $^{100}$Sn and nuclei in its vicinity. Among them are the boundaries of proton dripline, the effect of $pn$ interaction in self-conjugate nuclei, and the decay properties required for $rp$-process calculations in nucleosynthesis models. Despite many studies, experimental knowledge of these nuclides has remained scarce due to low production cross sections and a lack of intense beams. However, record quantities of exotic $N \simeq Z$ isotopes around $^{100}$Sn were produced at RIKEN Radioactive Isotope Beam Factory, via fragmentation of a $^{124}$Xe beam on a thin $^{9}$Be target. Based on the obtained data, $^{89}$Rh and $^{93}$Ag have been confirmed to be proton unbound [1]. Half-lives of isotopes near the proton dripline will be presented with improved precision compared to literature values. In addition, strategies to determine $Q_\beta$ for $ft$ values, and consequently the Fermi/Gamow-Teller transition strengths of these isotope decays will be discussed. [1] I. Celikovic et al., Phys. Rev. Lett. 116, 162501(2016).