407 research outputs found
Supersymmetry and Identical Bands
Supersymmetry as applied to identical bands is discussed. A review of the
work of the Koeln-Dubna group on this topic is given and examples in 171,172Yb,
173,174Hf, and 195,194Pt are discussed. The role of pseudo-spin in the
supersymmetry is investigated. A recent precision lifetime measurement for
identical bands in 171,172Yb is discussed.Comment: 14 pages, 5 figures, Erice conference 200
Quasideuteron states with deformed core
The M1 transitions between low-lying T=1 and T=0 states in deformed odd-odd
N=Z nuclei are analyzed in the frames of the rotor-plus-particle model. Using
the representation of an explicit coupling of angular momenta we show that
strong coupling of the quasideuteron configurations to the axially deformed
core results in a distribution of the total 0+ --> 1+ strength among a few
low-lying 1+ states. Simple analytical formulae for B(M1) values are derived.
The realization of the M1 sum rule for the low-lying 1+,T=0 states is
indicated. The calculated B(M1) values are found to be in good agreement with
experimental data and reveal specific features of collectivity in odd-odd N=Z
nuclei.Comment: 11 pages, 1 figure, LaTe
Crossing of two Coulomb-Blockade Resonances
We investigate theoretically the transport of non--interacting electrons
through an Aharanov--Bohm (AB) interferometer with two quantum dots (QD)
embedded into its arms. In the Coulomb-blockade regime, transport through each
QD proceeds via a single resonance. The resonances are coupled through the arms
of the AB device but may also be coupled directly. In the framework of the
Landauer--Buttiker approach, we present expressions for the scattering matrix
which depend explicitly on the energies of the two resonances and on the AB
phase. We pay particular attention to the crossing of the two resonances.Comment: 15 pages, 1 figur
Quasideuteron configurations in 46V and 58Cu
The data on low spin states in the odd-odd nuclei 46V and 58Cu investigated
with the 46Ti(p,ngamma)46V, 32S(16O,pn)46V and 58Ni(p,ngamma)58Cu reactions at
the FN-TANDEM accelerator in Cologne are reported. The states containing large
quasideuteron components are identified from the strong isovector M1
transitions, from shell model calculations and from experimental data for
low-lying states.Comment: 6 pages, 3 figures, proceedings of the "Nuclear Structure 2000"
conference, East Lansing, Michigan, USA, August 15-19, 2000; to appear in
Nucl. Phys.
Alternative Interpretation of Sharply Rising E0 Strengths in Transitional Regions
It is shown that strong 0+2 -> 0+1 E0 transitions provide a clear signature
of phase transitional behavior in finite nuclei. Calculations using the IBA
show that these transition strengths exhibit a dramatic and robust increase in
spherical-deformed shape transition regions, that this rise matches well the
existing data, that the predictions of these E0 transitions remain large in
deformed nuclei, and that these properties are intrinsic to the way that
collectivity and deformation develop through the phase transitional region in
the model, arising from the specific d-boson coherence in the wave functions,
and that they do not necessarily require the explicit mixing of normal and
intruder configurations from different IBA spaces.Comment: 6 pages, 3 figure
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