Speaker
Volker Werner
(Yale University)
Description
Isotopes below Nickel about N=40 are known to exhibit enhanced
collectivity, instead of signatures of an N=40 sub-shell closure which
is evident in 68Ni. The enhancement of collectivity has been seen in
Fe and Cr isotopes in the region through the lowering of 2+1 energies
as well as rise in B(E2) excitation strengths, mainly due to an early
population of the neutron g9/2 orbital. We intend to test the
persistence of this onset of collectivity to lower-Z isotopes, namely
Ti, just above the Ca Z=20 magic shell closure. Shell model
calculations from different groups predict a siginificant lowering of
the neutron d5/2 orbit and a presence of a new "island of inversion"
in the region, or rather significant populations of the g9/2
orbital. In either case this would lead to a softening of the N=50
shell closure, and thus an enhanced collectivity in heavy Ti isotopes.
To study the single particle structure of heavy Ti isotopes up to
A=62, energies of the lowest excited states in even-even nuclei are
important, as well as their B(E2) excitation strength, and effective
single-particle energies of the relevant orbitals may be deduced from
the odd-A Ti isotopes. While in the lighter Ti's up to about A=60
Coulomb excitation to the first excited states should be possible with
RIBF intensities and using DALI2. Excited states in the heavier
isotopes, especially those higher than the first excited state, can
only be reached via knockout reactions. The availability of MINOS in
conjunction with DALI2 would offer a steep rise in cross-section for
this type of experiments.
Primary author
Volker Werner
(Yale University)
