228 research outputs found
Effect of Coriolis Interaction on the Decay of Isotones with N = 149 and N = 153
© 2018, Allerton Press, Inc. The quasi-neutron structure of nuclei in two chains of odd isotones with N = 149 and N = 153:243,247Pu,245,249Cm,247,251Cf,249,253Fm,251,255No, and is considered. Single-particle energy spectra are calculated using the two center shell model (TCSM). Minimizing the potential energy with respect to the collective coordinates gives the ground state of the studied nucleos, which is subsequently used to describe low-lying quasi-neutron states. The K-mixing of the basis TCSM wave functions is considered by including the Coriolis correction in the total Hamiltonian of the system. The effect of level blocking is also considered in the calculations. The probabilities of the E2 transitions to the ground states and the corresponding lifetimes of the quasi-neutron levels are estimated
Multi-step particle emission probabilities in superheavy nuclei at moderate excitation energies
The probabilities of -, -, and -evaporation channels in
excited superheavy nuclei were evaluated using the Monte Carlo method. The
calculations utilized microscopically determined nuclear level densities and
were compared with results obtained from the phenomenological Jackson formula.
Effective temperatures derived from the microscopic approach were incorporated
into the Jackson formula for different evaporation channels at low and moderate
excitation energies. Additionally, an analytical formula was introduced to
estimate the average kinetic energy of emitted particles in multi-step
processes.Comment: 10 pages, 3 figure
Entropies, level-density parameters, and fission probabilities along the triaxially- and axially-symmetric fission paths in Lv
We employ a statistical approach to investigate the influence of axial
asymmetry on the nuclear level density and entropy along the fission pathways
of a superheavy nucleus, explicitly focusing on the Lv isotope. These
pathways are determined within multidimensional deformation spaces. Our
analysis reveals a significant impact of triaxiality on entropy. Additionally,
suppressing shell effects can alter the fission scenario depending on the
available excitation energy. We derive the deformation-dependent level density
parameter, which plays a crucial role in estimating the survival probability of
a superheavy nucleus. Furthermore, we utilize a set of master equations to
obtain the time-dependent fission probabilities and calculate the ratio of
decay probabilities for both axial and triaxial paths.Comment: submitted to PR
Clustering and Sharing Incentives in BitTorrent Systems
Peer-to-peer protocols play an increasingly instrumental role in Internet
content distribution. Consequently, it is important to gain a full
understanding of how these protocols behave in practice and how their
parameters impact overall performance. We present the first experimental
investigation of the peer selection strategy of the popular BitTorrent protocol
in an instrumented private torrent. By observing the decisions of more than 40
nodes, we validate three BitTorrent properties that, though widely believed to
hold, have not been demonstrated experimentally. These include the clustering
of similar-bandwidth peers, the effectiveness of BitTorrent's sharing
incentives, and the peers' high average upload utilization. In addition, our
results show that BitTorrent's new choking algorithm in seed state provides
uniform service to all peers, and that an underprovisioned initial seed leads
to the absence of peer clustering and less effective sharing incentives. Based
on our observations, we provide guidelines for seed provisioning by content
providers, and discuss a tracker protocol extension that addresses an
identified limitation of the protocol
Cluster Interpretation of Properties of Alternating Parity Bands in Heavy Nuclei
The properties of the states of the alternating parity bands in actinides,
Ba, Ce and Nd isotopes are analyzed within a cluster model. The model is based
on the assumption that cluster type shapes are produced by the collective
motion of the nuclear system in the mass asymmetry coordinate. The calculated
spin dependences of the parity splitting and of the electric multipole
transition moments are in agreement with the experimental data.Comment: 29 pages, 10 figure
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