Mapping of a New Deformation Region around $^{62}$Ti

概要

We performed the first direct mass measurements of neutron-rich scandium, titanium, and vanadium isotopes around the neutron number 40 at the RIKEN RI Beam Factory using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of $^{58−60}$Sc, $^{60−62}$Ti, and $^{62−64}$V were measured for the first time. The experimental results show that the two-neutron separation energies in the vicinity of $^{62}$Ti increase compared to neighboring nuclei. This shows that the masses of Ti isotopes near N = 40 are affected by the Jahn-Teller effect. Therefore, a development of Jahn-Teller stabilization appears below the Cr isotopes, and the systematics in Sc, Ti, and V isotopes suggest that $^{62}$Ti is located close to the peak of the Jahn-Teller effect.