Triaxial projected shell model description of high-spin band-structures in 103,105Rh isotopes
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Open Access
Abstract
High-spin band structures in odd-proton 103,105Rh
are investigated using the microscopic triaxial projected shell model
approach. It is demonstrated that the observed band structures built on
one- and three-quasiparticle states are reproduced reasonably well in
the present work. Further, it is evident from the analysis of the
projected wavefunctions that side-band in the low-spin regime is the
normal γ-band built on the ground-state configuration. However,
in the high-spin regime, the side band is shown to be highly mixed and
ceases to be a γ-band. We provide a complete set of
electromagnetic transition probabilities for the two bands and the
experimental measurements are desirable to test the predictions of the
present work.
Recently,
high-spin band structures in mass ∼100 and 130 regions have been
investigated quite vigorously due to observation of doublet band
structures, possibly originating from breaking of the chiral symmetry in
the intrinsic frame of reference [1], [2] and [3]. A systematic study of the experimental features of ΔI=1 doublet bands and their interpretation has been reviewed in Ref. [4].
Earlier studies reported the observation of doublet band structures in
several odd–odd nuclei in the two mass regions that are based on
two-quasiparticle excitations [5], [6], [7], [8], [9], [10], [11], [12] and [13].
It has been demonstrated using phenomenological approaches that for the
doublet band structures to arise from the restoration of chiral
symmetry breaking mechanism, two experimental criteria must be
fulfilled. First, the observation of two nearly degenerate ΔI=1 bands and second the two bands having identical electromagnetic properties, i.e., similar B(M1) and B(E2)
values for in-band and inter-band transitions. Lifetime measurements of
doublet band structures in several nuclei revealed that the second
criterion is not fulfilled by many nuclei and the interpretation of
these bands as chiral partners is erroneous [14], [15] and [16]. In particular, for the doublet bands in 134Pr that exhibit the best overall energy degeneracy, lifetime measurements revealed that B(M1) values are, although, similar but B(E2)
values of the main band are a factor of 2–3 larger than that of the
partner band and, therefore, the two bands cannot arise from the chiral
symmetry breaking [17] and [18].
