Ponente
Descripción
The island of inversion, where the ground and excited states exchange their nuclear deformation, is one of the cornerstones to investigate nuclear shell evolution in nuclei with the extreme neutron-proton ratios. $^{64}$Cr is the key nucleus for this island of inversion at N = 40 with multi particle and multi hole (np-nh) configurations. Recently, the in-beam $\gamma$-ray spectroscopy carried out at FRIB measured the $0^{+}_{2}$ state in $^{62}$Cr with angular momentum distribution [A. Gade et al., Nat. Phys. 21, 37 (2025)]. From this measurement, the ground state was suggested to be formed by the 4p-4h configuration while the excited $0^{+}$ state originated from the 2p-2h configuration by comparing with theoretical predictions. These findings opened a portal to the island of inversion and shape coexistence in this N = 40 region.
In this presentation, we propose to measure the excited states in even-even Ti and Cr isotopes other than ground band structures to thoroughly investigate the np-nh configurations through the $\beta$-delayed $\gamma$-ray spectroscopy. Particularly, we point out that $^{60}$Ti and $^{64}$Cr nuclei, the isotone and isotope of $^{62}$Cr, respectively, play important roles in this island of inversion and shape coexistence.
