3,095 research outputs found
Systematic investigation of the rotational bands in nuclei with using a particle-number conserving method based on a cranked shell model
The rotational bands in nuclei with are investigated
systematically by using a cranked shell model (CSM) with the pairing
correlations treated by a particle-number conserving (PNC) method, in which the
blocking effects are taken into account exactly. By fitting the experimental
single-particle spectra in these nuclei, a new set of Nilsson parameters
( and ) and deformation parameters ( and
) are proposed. The experimental kinematic moments of inertia
for the rotational bands in even-even, odd- and odd-odd nuclei, and the
bandhead energies of the 1-quasiparticle bands in odd- nuclei, are
reproduced quite well by the PNC-CSM calculations. By analyzing the
-dependence of the occupation probability of each cranked Nilsson
orbital near the Fermi surface and the contributions of valence orbitals in
each major shell to the angular momentum alignment, the upbending mechanism in
this region is understood clearly.Comment: 21 pages, 24 figures, extended version of arXiv: 1101.3607 (Phys.
Rev. C83, 011304R); added refs.; added Fig. 4 and discussions; Phys. Rev. C,
in pres
Cactus Representations in Polylogarithmic Max-flow via Maximal Isolating Mincuts
A cactus representation of a graph, introduced by Dinitz et al. in 1976, is
an edge sparsifier of size that exactly captures all global minimum cuts
of the graph. It is a central combinatorial object that has been a key
ingredient in almost all algorithms for the connectivity augmentation problems
and for maintaining minimum cuts under edge insertions (e.g. [NGM97], [CKL+22],
[Hen97]). This sparsifier was generalized to Steiner cactus for a vertex set
, which can be seen as a vertex sparsifier of size that captures
all partitions of corresponding to a -Steiner minimum cut, and also
hypercactus, an analogous concept in hypergraphs. These generalizations further
extend the applications of cactus to the Steiner and hypergraph settings.
In a long line of work on fast constructions of cactus and its
generalizations, a near-linear time construction of cactus was shown by [Karger
and Panigrahi 2009]. Unfortunately, their technique based on tree packing
inherently does not generalize. The state-of-the-art algorithms for Steiner
cactus and hypercactus are still slower than linear time by a factor of
[DV94] and [CX17], respectively.
We show how to construct both Steiner cactus and hypercactus using
polylogarithmic calls to max flow, which gives the first almost-linear time
algorithms of both problems. The constructions immediately imply
almost-linear-time connectivity augmentation algorithms in the Steiner and
hypergraph settings, as well as speed up the incremental algorithm for
maintaining minimum cuts in hypergraphs by a factor of .
The key technique behind our result is a novel variant of the influential
isolating mincut technique [LP20, AKL+21] which we called maximal isolating
mincuts. This technique makes the isolating mincuts to be "more balanced"
which, we believe, will likely be useful in future applications.Comment: To appear in SODA 202
The General Characteristics of Electromagnetic Radiation During Coal Fracture and Its Application in Outburst Prediction
Coal and methane outburst are catastrophic in coal mining, their prediction is difficult. In this paper, the electromagnetic radiation (EMR) generated during coal or rock deformation and fracturing is measured and analyzed. The results show that EMR truly exists during the fracture of coal or rock (with or without the presence of gas). It follows the Hurst statistical rule, and it basically exhibits gradually enhancing tendency during the process. The EMR strength and frequency are correlated to the coal or rock fracture process. Based on the experimental and theoretical studies, a new method for coal and methane outburst prediction is proposed -the EMR method. This new method significantly facilitates methane outburst prediction
Rotation and alignment of high- orbitals in transfermium nuclei
The structure of nuclei with is investigated systematically by the
Cranked Shell Model (CSM) with pairing correlations treated by a
Particle-Number Conserving (PNC) method. In the PNC method, the particle number
is conserved and the Pauli blocking effects are taken into account exactly. By
fitting the experimental single-particle spectra in these nuclei, a new set of
Nilsson parameters ( and ) is proposed. The experimental kinematic
moments of inertia and the band-head energies are reproduced quite well by the
PNC-CSM calculations. The band crossing, the effects of high- intruder
orbitals and deformation are discussed in detail.Comment: To appear in the Proceedings of the International Nuclear Physics
Conference (INPC2013), June 2-7, 2013, Florence, Ital
Inclusive weak-annihilation decays and lifetimes of beauty-charmed baryons
Imbalanced beauty-charmed baryons are of great
significance to the development of heavy flavor physics. In this work, we study
the inclusive weak-annihilation decays of and their
contributions to the lifetimes. For the calculation of the
inclusive decay width where stands for the
sum of the final states with charm number +1 and strange number -1, we work in
the heavy diquark effective theory which provides us with a convenient
technical tool to construct the operator product expansion. The
is considered to be a superposition of two states with one
containing a spin-0 diquark and the other one containing a spin-1
diquark. It is found that both the lifetimes and the
branching ratios are very sensitive to the spin
in . As has a longer lifetime than
and bigger branching ratios of similar decay channels, the exclusive decays
, ,
, and are more
promising for experimental searches of at the LHC comparing
with exclusive decay .Comment: 7 pages, 4 figure
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