ausblenden:
Schlagwörter:
Nuclear Experiment, nucl-ex,Nuclear Theory, nucl-th
MPINP:
Starke Wechselwirkung und exotische Kerne – Abteilung Blaum
Zusammenfassung:
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.
