19 research outputs found
Low-lying 2 states generated by -quadrupole correlation and shell quenching
The quadrupole vibrational modes of neutron-rich =28 isotones (Ca,
Ar, S and Si) are investigated using the canonical-basis
time-dependent Hartree-Fock-Bogoliubov theory with several choice of energy
density functionals, including nuclear pairing correlation. It is found that
the quenching of =28 shell gap and the proton holes in the -shell
trigger quadrupole correlation and increase the collectivity of the low-lying
2 state in Ar. It is also found that the pairing correlation plays
an important role to increase the collectivity. We also demonstrate that the
same mechanism to enhance the low-lying collectivity applies to other =28
isotones S and Si, and it generates a couple of low-lying 2
states which can be associated with the observed states.Comment: 7 page and 4 figure