Speaker
Prof.
Masayuki Matsuzaki
(Fukuoka University of Education)
Description
Two phonon $\gamma$ vibrational states in even-even nuclei were observed
in a few nuclides in the rare-earth region and stimulated many theoretical
studies in the 80s and 90s but those in rotating odd-$A$ nuclei were observed
only recently. Distribution of the two phonon $\gamma$ vibrational collectivity
in the rotating triaxial neutron-rich odd-$A$ nucleus, $^{103}$Nb,
is calculated in the framework of the particle vibration coupling
model based on the cranked shell model plus random phase approximation.
This nucleus is one of the three for which experimental data
obtained by measuring prompt $\gamma$ rays emitted by the spontaneous
fission fragments of $^{252}$Cf were reported recently.
The present theoretical framework was previously utilized
for analyses of the zero and one phonon bands in the rare-earth region
and is applied to the two phonon band for the first time.
In the present calculation, the zero and one phonon bands are reproduced
almost perfectly but the excitation energy of the calculated two phonon band
is higher than the observed. The point to be stressed is that three sequences
of two phonon bands share collectivity almost equally at finite
rotation whereas the $K=\Omega+4$ state is the purest at zero rotation.
Primary author
Prof.
Masayuki Matsuzaki
(Fukuoka University of Education)
