Lanthanum Isotopes in a Possible New Region of Nuclear Deformation

Abstract

New neutron-deficient lanthanum isotopes have been produced by heavy-ion bombardments of indium, and identified by means of chemical separations and genetic relationships. The proposed mass assignments and corresponding half-lives are: ${\mathrm{La}}^{124}$, 7.2\ifmmode\pm\else\textpm\fi{}0.5 min; ${\mathrm{La}}^{128}$, 4.2\ifmmode\pm\else\textpm\fi{}0.5 min; ${\mathrm{La}}^{127}$, 3.8\ifmmode\pm\else\textpm\fi{}0.5 min; ${\mathrm{La}}^{126}$, 1.0\ifmmode\pm\else\textpm\fi{}0.3 min; and ${\mathrm{La}}^{125}$, 1 min.