New Region of Deformation: The Neutron-Rich Sulfur Isotopes

Abstract

The energies and $B({E2;0}_{\mathrm{g}.\mathrm{s}.}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ values for the lowest ${J}^{\ensuremath{\pi}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2}^{+}$ states in the neutron-rich radioactive nuclei ${}^{38,40,42}\mathrm{S}$ and ${}^{44,46}\mathrm{Ar}$ were measured via intermediate-energy Coulomb excitation. The results for ${}^{40,42}\mathrm{S}$ provide the first evidence of moderate deformation near $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28$, while the effects of the $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28$ shell closure persist in the $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}18$ nucleus ${}^{46}\mathrm{Ar}$.