5,847 research outputs found
Inclusive quasi-elastic electron-nucleus scattering
This article presents a review of the field of inclusive quasi-elastic
electron-nucleus scattering. It discusses the approach used to measure the data
and includes a compilation of data available in numerical form. The theoretical
approaches used to interpret the data are presented. A number of results
obtained from the comparison between experiment and calculation are then
reviewed. The analogies and differences to other fields of physics exploiting
quasi-elastic scattering from composite systems are pointed out.Comment: Accepted for publication in Reviews of Modern Physic
Comments on differential cross section of phi-meson photoproduction at threshold
We show that the differential cross section d_sigma/d_t of gamma p --> \phi p
reaction at the threshold is finite and its value is crucial to the mechanism
of the phi meson photoproduction and for the models of phi-N interaction.Comment: 8 pages, 2 figure
The Emergence of a Twisted Flux Tube into the Solar Atmosphere: Sunspot Rotations and the Formation of a Coronal Flux Rope
We present a 3D simulation of the dynamic emergence of a twisted magnetic
flux tube from the top layer of the solar convection zone into the solar
atmosphere and corona. It is found that after a brief initial stage of flux
emergence during which the two polarities of the bipolar region become
separated and the tubes intersecting the photosphere become vertical,
significant rotational motion sets in within each polarity. The rotational
motions of the two polarities are found to twist up the inner field lines of
the emerged fields such that they change their orientation into an inverse
configuration (i.e. pointing from the negative polarity to the positive
polarity over the neutral line). As a result, a flux rope with sigmoid-shaped,
dipped core fields form in the corona, and the center of the flux rope rises in
the corona with increasing velocity as the twisting of the flux rope footpoints
continues. The rotational motion in the two polarities is a result of
propagation of non-linear torsional Alfv\'en waves along the flux tube, which
transports significant twist from the tube's interior portion towards its
expanded coronal portion. This is a basic process whereby twisted flux ropes
are developed in the corona with increasing twist and magnetic energy, leading
up to solar eruptions.Comment: 33 pages, 14 figures, Submitted to Ap
Investigation of search points for the point of maximum power for the increasing signal inverter voltage transducer
Endpoint distribution of directed polymers in 1+1 dimensions
We give an explicit formula for the joint density of the max and argmax of
the Airy process minus a parabola. The argmax has a universal distribution
which governs the rescaled endpoint for large time or temperature of directed
polymers in 1+1 dimensions.Comment: Expanded introductio
Electronic structure of Co_xTiSe_2 and Cr_xTiSe_2
The results of investigations of intercalated compounds Cr_xTiSe_2 and
Co_xTiSe_2 by X-ray photoelectron spectroscopy (XPS) and X-ray emission
spectroscopy (XES) are presented. The data obtained are compared with
theoretical results of spin-polarized band structure calculations. A good
agreement between theoretical and experimental data for the electronic
structure of the investigated materials has been observed. The interplay
between the M3d--Ti3d hybridization (M=Cr, Co) and the magnetic moment at the M
site is discussed. A 0.9 eV large splitting of the core Cr2p{3/2} level was
observed, which reveals a strong exchange magnetic interaction of 3d-2p
electrons of Cr. In the case of a strong localization of the Cr3d electrons
(for x<0.25), the broadening of the CrL spectra into the region of the states
above the nominal Fermi level was observed and attributed to X-ray re-emission.
The measured kinetic properties are in good accordance with spectral
investigations and band calculation results.Comment: 14 pages, 11 figures, submitted to Phys.Rev.
Resonant photoemission at the absorption edge of Mn and Ti and electronic structure of 1T-MnTiSe
Resonant valence-band X-ray photoelectron spectra (ResPES) excited near
2p core level energies, 2p X-ray photoelectron spectra (XPS) and
L X-ray absorption spectra (XAS) of Ti and Mn in single crystal of
1T-MnTiSe were studied for the first time. The ionic-covalent character
of bonds formed by Mn atoms with the neighboring Se atoms in the octahedral
coordination is established. From the XPS and XAS measurements compared with
results of atomic multiplet calculations of Ti and Mn L XAS it is found
that Ti atoms are in ionic state of 4+ and Mn atoms are in the state of 2+. In
ResPES of MnTiSe excited near Ti 2p and Mn 2p
absorption edges the Ti 3d and Mn 3d bands at binding energies just below the
Fermi level are observed. According to band structure calculations
E the Ti 3d states are localized in the vicinity of
point and the Mn 3d states are localized along the direction
K--M in the Brillouin zone of the crystal.Comment: 18 pages (preprint), 9 figure
Parity violation in deuteron photo-disintegration
We analyze the energy dependence for two types of parity-non-conserving
(PNC) asymmetries in the reaction in the near-threshold
region. The first one is the asymmetry in reaction with circularly polarized
photon beam and unpolarized deuteron target. The second one corresponds to
those with an unpolarized photon beam and polarized target. We find that the
two asymmetries have quite different energy dependence, and their shapes are
sensitive to the PNC-meson exchange coupling constants.
The predictions for the future possible experiments to provide definite
constraints for the PNC-coupling constants are discussed.Comment: 22 pages, 12 figures. Submitted to Phys.Rev.C 10Oct.0
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