75 research outputs found
From chiral vibration to static chirality in ^{135}Nd
Electromagnetic transition probabilities have been measured for the intra-
and inter-band transitions in the two sequences in the nucleus ^{135}Nd that
were previously identified as a composite chiral pair of rotational bands. The
measurements are in good agreement with results of a new combination of TAC and
RPA calculations. The chiral character of the bands is affirmed and it is shown
that their behavior is associated with a transition from a vibrational into a
static chiral regime.Comment: Accepted for publication in the Physical Review Letters. Small
modifications to fit the length limits of the journal. 10 pages, 4 figure
In-beam spectroscopy of medium- and high-spin states in Ce
Medium and high-spin states in Ce were investigated using the
Cd(Ne, ) reaction and the Gammasphere array. The level
scheme was extended up to an excitation energy of MeV and spin 93/2
. Eleven bands of quadrupole transitions and two new dipole bands are
identified. The connections to low-lying states of the previously known,
high-spin triaxial bands were firmly established, thus fixing the excitation
energy and, in many cases, the spin parity of the levels. Based on comparisons
with cranked Nilsson-Strutinsky calculations and tilted axis cranking covariant
density functional theory, it is shown that all observed bands are
characterized by pronounced triaxiality. Competing multiquasiparticle
configurations are found to contribute to a rich variety of collective
phenomena in this nucleus.Comment: 20 pages, 11 figure
Lifetime measurements of Triaxial Strongly Deformed bands in Tm
With the Doppler Shift Attenuation Method, quadrupole transition moments,
, were determined for the two recently proposed Triaxial Strongly Deformed
(TSD) bands in Tm. The measured moments indicate that the
deformation of these bands is larger than that of the yrast, signature
partners. However, the measured values are smaller than those predicted by
theory. This observation appears to be valid for TSD bands in several nuclei of
the regionComment: 8 pages, 5 figures. Submitted to Physical Review
Evidence for Multiple Chiral Doublet Bands in Ce
Two distinct sets of chiral-partner bands have been identified in the nucleus
Ce. They constitute a multiple chiral doublet (MD), a phenomenon
predicted by relativistic mean field (RMF) calculations and observed
experimentally here for the first time. The properties of these chiral bands
are in good agreement with results of calculations based on a combination of
the constrained triaxial RMF theory and the particle-rotor model.Comment: Minor changes based on referee reviews and corrections of some typo
Rotation of pear-shaped Ru nucleus
Atomic nuclei in general can have deformed shapes and nearly all these shapes
are symmetric with respect to reflection. Only a few Actinide nuclei have
stable reflection asymmetric pear shapes in their ground state and exhibit
characteristic rotational bands. In this article, we report on the observation
of two alternate parity rotational bands in 100Ru, which are connected by seven
interleaved electric dipole transitions and their rates are found to be
enhanced. In addition, the moments of inertia associated with these two
opposite parity rotational bands have been found to be similar. These
experimental observations indicate the rotation of a stable pear-shaped 100Ru
nucleus, which is the first such observation outside the Actinide mass region.
This shape is built on an excited configuration and originates from the
rotational alignment of the angular momenta of a pair of neutrons. This unique
observation establishes an alternate mechanism by which an atomic nucleus can
assume a pear shape.Comment: 13 pages, 7 figures, 2 table
Study of nuclei in the vicinity of the "Island of Inversion" through fusion-evaporation reaction
We report the first observation of high-spin states in nuclei in the vicinity
of the "island of inversion", populated via the 18O+18O fusion reaction at an
incident beam energy of 34 MeV. The fusion reaction mechanism circumvents the
limitations of non-equilibrated reactions used to populate these nuclei.
Detailed spin-parity measurements in these difficult to populate nuclei have
been possible from the observed coincidence anisotropy and the linear
polarization measurements. The spectroscopy of 33,34P and 33S is presented in
detail along with the results of calculations within the shell model framework
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