Prof.
Stefan Frauendorf
(Research Center Dresden-Rossendorf, Germany)
03/04/2008, 13:15
Exotic deformation / new collective motion at low and high spin
Invited Presentation
An overview of selected recent experimental results is given. Their impact on our understanding of nuclear structure is discussed. The following subjects are touched: Termination of regular bands and their recurrance, hyperdeformation,
triaxial strongly deformed bands and wobbling, chirality, isospin breaking in mirror nuclei, isomers in the heaviest elements and their implications for...
Dr
Rudrajyoti Palit
(Tata Institute of Fundamental Research)
03/04/2008, 14:00
Exotic deformation / new collective motion at low and high spin
Presentation
The nuclei in the mass $A\sim130$ region below N = 82 shell closure are soft to gamma-deformation at low and medium spins, and exhibit various intriguing
phenomena. Depending upon the coupling of the angular momenta of valance
neutrons and protons with that of the even-even core different types of
excitations [1 - 4], namely, magnetic rotation, chiral twin
bands and recently predicted...
Prof.
Umesh Garg
(University of Notre Dame)
03/04/2008, 14:40
Dr
Tomokazu Suzuki
(Department of Physics, Osaka univ.)
03/04/2008, 15:10
Exotic deformation / new collective motion at low and high spin
Presentation
A spontaneous symmetry breaking is a common keyword in modern physics.
Chiral symmetry breaking in nuclear structure has recently been debated.
This phenomenon is related to time reversal
and arises from mutually perpendicular angular momenta of the
valence proton, valence neutron, and core rotation in the body fixed frame.
The nuclear chirality results in a nearly degenerate pair...
Dr
Michael Carpenter
(Argonne National Laboratory)
03/04/2008, 15:30
Exotic deformation / new collective motion at low and high spin
Invited Presentation
Gammasphere has been in operation for over 10 years. In the initial
years, it was used almost exclusively to study nuclei produced in
fusion evaporation reactions at high spin. For example, successful
campaigns to study and characterize superdeformation throughout the
nucleonic chart were performed. In recent years, many experiments have
been directed at the study of nuclei near the...
Dr
Tsuneyasu Morikawa
(Department of Physics, Kyushu University)
03/04/2008, 16:00
Exotic deformation / new collective motion at low and high spin
Presentation
Progress of the RI beam physics has revealed the new interesting phenomena such as neutron halo and island of inversion. Theoretically, the breakdown of the well-known N = 20 magic number in the island of inversion is interpreted in term of the lowering of 2p-2h energy gap. Experimentally, however, the knowledge on the
nuclear structure is so far limited to ground states and lowest-lying...
Dr
Hooi Jin Ong
(RCNP, Osaka University)
05/04/2008, 11:00
Collectivities and shell effects in neutron/proton-rich nuclei
Presentation
The reduced E2 transition probability from the first excited 2+ (2^+_1) state to the ground state --- B(E2) --- of an even-even nucleus is an important observable that reflects proton collectivity. Recently, an anomalously small B(E2) was reported for the neutron-rich 16C nucleus [1]. The result points to a suppressed proton contribution to the transition strength. This finding raises an...
Dr
Paul Fallon
(Lawrence Berkeley Laboratory)
05/04/2008, 11:20
Collectivities and shell effects in neutron/proton-rich nuclei
Presentation
The observation of either enhanced or reduced transition strengths (collectivity) can signal unexpected changes in nuclear structure. In light neutron-rich nuclei both phenomena have been reported and both have led to unexpected results and new insights.
An example of the former is found in the “island of inversion”. First observed through an increased binding in 31Na, the N=20 isotones...
Dr
Zoltan Elekes
(MTA ATOMKI)
05/04/2008, 11:40
Exotic deformation / new collective motion at low and high spin
Presentation
In recent years, significantly different contribution of neutrons and protons to the first excited states has been observed in several, light, neutron-rich nuclei. Especially, carbon isotopes have been intensively studied, but 20C, the heaviest isotope reachable with the present experimental facilities, was not investigated. In order to make the measurements complete in the carbon isotopic...
Mr
Shinsuke Ota
(Center for Nuclear Study, University of Tokyo)
05/04/2008, 12:00
Collectivities and shell effects in neutron/proton-rich nuclei
Presentation
We have measured the proton transfer reaction of $^{4}$He($^{12}$Be,$^{13}$B$\gamma$) with ``Gamma-Ray detector Array
with Position and Energy sensitivity (CNS-GRAPE)'' in RIKEN.
Analyzing the angular differential cross section, we assigned the $J^{\pi}$ of 4.83~MeV excited state to be $1/2{+}$ with $C^{2}S=0.2$, for the first time.
This state is interpreted as a proton intruder state from...
Dr
Makito Oi
(Department of Physics, University of Surrey)
05/04/2008, 15:10
Exotic deformation / new collective motion at low and high spin
Presentation
Superdeformed states have been populated exclusively with the
fusion-evaporation reactions, which is suitable for a productin
of very high-spin states. This is possible through neutron evapolations
that do not take angular momentum away from the system.
However, as a consequence, such a high-spin states can be produced
only for neutron-deficient systems.
A $N=Z$ nucleus...
Yasutaka TANIGUCHI
(Kyoto Univ. (-March, 2008))
05/04/2008, 15:30
Exotic deformation / new collective motion at low and high spin
Presentation
We have studied clustering and deformations in $^{40}$Ca using the antisymmetrized molecular dynamics (AMD) and generator coordinate method (GCM).
The GCM basis are obtained by energy variation with two kinds of constraints for clustering and deformations, respectively.
Superposing obtained wave functions, which form mean-field-type, $\alpha$-$^{36}$Ar, and $^{12}$C-$^{28}$Si structures,...
Prof.
Tadashi Shimoda
(Department of Physics, Osaka University)
05/04/2008, 15:50
Collectivities and shell effects in neutron/proton-rich nuclei
Presentation
Evolution of shell structures in a wide range of nuclear
chart is one of the most important subjects in nuclear
physics. In particular, breakdown of the $N=20$ shell
closure and onset of collectivity as increasing neutron
number in neutron-rich nuclei in the region of so-called
``island of inversion". In spite of intensive investigations
for many years, little is known on the...
