632 research outputs found
Exploration of Resonant Continuum and Giant Resonance in the Relativistic Approach
Single-particle resonant-states in the continuum are determined by solving
scattering states of the Dirac equation with proper asymptotic conditions in
the relativistic mean field theory (RMF). The regular and irregular solutions
of the Dirac equation at a large radius where the nuclear potentials vanish are
relativistic Coulomb wave functions, which are calculated numerically.
Energies, widths and wave functions of single-particle resonance states in the
continuum for ^{120}Sn are studied in the RMF with the parameter set of NL3.
The isoscalar giant octupole resonance of ^{120}Sn is investigated in a fully
consistent relativistic random phase approximation. Comparing the results with
including full continuum states and only those single-particle resonances we
find that the contributions from those resonant-states dominate in the nuclear
giant resonant processes.Comment: 16 pages, 2 figure
Continuous metal-insulator transition of the antiferromagnetic perovskite NaOsO3
Newly synthesized perovskite NaOsO3 shows Curie-Weiss metallic nature at high
temperature and suddenly goes into an antiferromagnetically insulating state at
410 K on cooling. Electronic specific heat at the low temperature limit is
absent, indicating that the band gap fully opens. In situ observation in
electron microscopy undetected any lattice anomalies in the vicinity of the
transition temperature. It is most likely that the antiferromagnetic
correlation plays an essential role of the gap opening.Comment: 13 pages, 5 figures, PHYS. REV. B 80, 161104(R),(2009
Statistics of level spacing of geometric resonances in random binary composites
We study the statistics of level spacing of geometric resonances in the
disordered binary networks. For a definite concentration within the
interval , numerical calculations indicate that the unfolded level
spacing distribution and level number variance have the
general features. It is also shown that the short-range fluctuation and
long-range spectral correlation lie between the profiles of the
Poisson ensemble and Gaussion orthogonal ensemble (GOE). At the percolation
threshold , crossover behavior of functions and is
obtained, giving the finite size scaling of mean level spacing and
mean level number , which obey the scaling laws, and .Comment: 11 pages, 7 figures,submitted to Phys. Rev.
Compact and Loosely Bound Structures in Light Nuclei
A role of different components in the wave function of the weakly bound light
nuclei states was studied within the framework of the cluster model, taking
into account of orbitals "polarization". It was shown that a limited number of
structures associated with the different modes of nucleon motion can be of
great importance for such systems. Examples of simple and quite flexible trial
wave functions are given for the nuclei Be, He. Expressions for the
microscopic wave functions of these nuclei were found and used for the
calculation of basic nuclear characteristics, using well known central-exchange
nucleon-nucleon potentials.Comment: 19 pages, 3 ps figure
State Dependent Effective Interaction for the Hyperspherical Formalism
The method of effective interaction, traditionally used in the framework of
an harmonic oscillator basis, is applied to the hyperspherical formalism of
few-body nuclei (A=3-6). The separation of the hyperradial part leads to a
state dependent effective potential. Undesirable features of the harmonic
oscillator approach associated with the introduction of a spurious confining
potential are avoided. It is shown that with the present method one obtains an
enormous improvement of the convergence of the hyperspherical harmonics series
in calculating ground state properties, excitation energies and transitions to
continuum states.Comment: LaTeX, 16 pages, 8 ps figure
SN 2016coi/ASASSN-16fp: An example of residual helium in a type Ic supernova?
The optical observations of Ic-4 supernova (SN) 2016coi/ASASSN-16fp, from
to days after explosion, are presented along with analysis
of its physical properties. The SN shows the broad lines associated with SNe
Ic-3/4 but with a key difference. The early spectra display a strong absorption
feature at \AA\ which is not seen in other SNe~Ic-3/4 at this
epoch. This feature has been attributed to He I in the literature. Spectral
modelling of the SN in the early photospheric phase suggests the presence of
residual He in a C/O dominated shell. However, the behaviour of the He I lines
are unusual when compared with He-rich SNe, showing relatively low velocities
and weakening rather than strengthening over time. The SN is found to rise to
peak d after core-collapse reaching a bolometric luminosity of Lp
\ergs. Spectral models, including the nebular epoch, show
that the SN ejected \msun\ of material, with \msun\ below
5000 \kms, and with a kinetic energy of erg. The
explosion synthesised \msun\ of 56Ni. There are significant
uncertainties in E(B-V)host and the distance however, which will affect Lp and
MNi. SN 2016coi exploded in a host similar to the Large Magellanic Cloud (LMC)
and away from star-forming regions. The properties of the SN and the
host-galaxy suggest that the progenitor had of \msun\
and was stripped almost entirely down to its C/O core at explosion.Comment: Accepted for publication in MNRAS. Updated to reflect the published
version, minor typographical changes onl
The laws about Virtual Museums in Russia: Museums Studies
Статья поступила в редакцию 15.01.2022 г.В статье характеризуются основные законодательные нормы функционирования виртуальных музеев в Российской Федерации на современном этапе. Авторы освещают проблемы музейного представительства в интернете, использования цифровых копий музейных предметов в Сети, их правовой статус, выявляют пробелы в сфере защиты интеллектуальной собственности и правового регулирования деятельности виртуальных музеев.Russian rules and policy concerning virtual museums and their activity are analyzed in the article. The authors revealed the current museums problems in the Internet, studied the possibilities of digital copies of museums’ artefacts application and their legal position. This article tends to favour the view that new forms of intellectual property protection are needed to adequately protect heritage in the Internet
Parallel momentum distribution of the Si fragments from P
Distribution of the parallel momentum of Si fragments from the breakup
of 30.7 MeV/nucleon P has been measured on C targets. The distribution
has the FWHM with the value of 110.5 23.5 MeV/c which is consistent
quantitatively with Galuber model calculation assuming by a valence proton in
P. The density distribution is also predicted by Skyrme-Hartree-Fock
calculation. Results show that there might exist the proton-skin structure in
P.Comment: 4 pages, 4 figure
Approaching the Gamow Window with Stored Ions : Direct Measurement of Xe 124 (p,γ) in the ESR Storage Ring
© 2019 American Physical Society. All rights reserved.We report the first measurement of low-energy proton-capture cross sections of Xe124 in a heavy-ion storage ring. Xe12454+ ions of five different beam energies between 5.5 and 8 AMeV were stored to collide with a windowless hydrogen target. The Cs125 reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and x-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron and γ widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.Peer reviewedFinal Published versio
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