학술논문
Shell evolution of $N=40$ isotones towards $^{60}$Ca: First spectroscopy of $^{62}$Ti
Document Type
Working Paper
Author
Cortés, M. L.; Rodriguez, W.; Doornenbal, P.; Obertelli, A.; Holt, J. D.; Lenzi, S. M.; Menéndez, J.; Nowacki, F.; Ogata, K.; Poves, A.; Rodríguez, T. R.; Schwenk, A.; Simonis, J.; Stroberg, S. R.; Yoshida, K.; Achouri, L.; Baba, H.; Browne, F.; Calvet, D.; Château, F.; Chen, S.; Chiga, N.; Corsi, A.; Delbart, A.; Gheller, J-M.; Giganon, A.; Gillibert, A.; Hilaire, C.; Isobe, T.; Kobayashi, T.; Kubota, Y.; Lapoux, V.; Liu, H. N.; Motobayashi, T.; Murray, I.; Otsu, H.; Panin, V.; Paul, N.; Sakurai, H.; Sasano, M.; Steppenbeck, D.; Stuhl, L.; Sun, Y. L.; Togano, Y.; Uesaka, T.; Wimmer, K.; Yoneda, K.; Aktas, O.; Aumann, T.; Chung, L. X.; Flavigny, F.; Franchoo, S.; Gašparić, I.; Gerst, R. -B.; Gibelin, J.; Hahn, K. I.; Kim, D.; Koiwai, T.; Kondo, Y.; Koseoglou, P.; Lee, J.; Lehr, C.; Linh, B. D.; Lokotko, T.; MacCormick, M.; Moschner, K.; Nakamura, T.; Park, S. Y.; Rossi, D.; Sahin, E.; Sohler, D.; Söderström, P. -A.; Takeuchi, S.; Toernqvist, H.; Vaquero, V.; Wagner, V.; Wang, S.; Werner, V.; Xu, X.; Yamada, H.; Yan, D.; Yang, Z.; Yasuda, M.; Zanetti, L.
Source
Physics Letters B, 800, 135071 (2020)
Subject
Language
Abstract
Excited states in the $N=40$ isotone $^{62}$Ti were populated via the $^{63}$V$(p,2p)$$^{62}$Ti reaction at $\sim$200~MeV/u at the Radioactive Isotope Beam Factory and studied using $\gamma$-ray spectroscopy. The energies of the $2^+_1 \rightarrow 0^{+}_{\mathrm{gs}}$ and $4^+_1 \rightarrow 2^+_1$ transitions, observed here for the first time, indicate a deformed $^{62}$Ti ground state. These energies are increased compared to the neighboring $^{64}$Cr and $^{66}$Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings. The shell-model calculations for $^{62}$Ti show a dominant configuration with four neutrons excited across the $N=40$ gap. Likewise, they indicate that the $N=40$ island of inversion extends down to $Z=20$, disfavoring a possible doubly magic character of the elusive $^{60}$Ca.