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Charge-density wave and magnetic phase diagram of chromium alloys
The magnetic phase diagrams of all dilute Cr alloys can be explained by a simple theoretical model with coupled spin- and charge-density waves and a finite electron reservoir. If the charge-density wave and electron reservoir are sufficiently large, the paramagnetic to commensurate spin-density wave transition becomes strongly first order, as found in Cr{sub 1- x}Fe{sub x} and Cr{sub 1-x}Si{sub x} alloys. The observed discontinuity of the slope dT{sub N}/dx at the triple point and the bending of the CI phase boundary are also natural consequences of this model
Anomaly analysis of Hawking radiation from Kaluza-Klein black hole with squashed horizon
Considering gravitational and gauge anomalies at the horizon, a new method
that to derive Hawking radiations from black holes has been developed by
Wilczek et al. In this paper, we apply this method to non-rotating and rotating
Kaluza-Klein black holes with squashed horizon, respectively. For the rotating
case, we found that, after the dimensional reduction, an effective U(1) gauge
field is generated by an angular isometry. The results show that the gauge
current and energy-momentum tensor fluxes are exactly equivalent to Hawking
radiation from the event horizon.Comment: 15 pages, no figures, the improved version, accepted by Eur. Phys. J.
Electronic structure of fluorides: general trends for ground and excited state properties
The electronic structure of fluorite crystals are studied by means of density
functional theory within the local density approximation for the exchange
correlation energy. The ground-state electronic properties, which have been
calculated for the cubic structures ,, , ,
, -, using a plane waves expansion of the wave
functions, show good comparison with existing experimental data and previous
theoretical results. The electronic density of states at the gap region for all
the compounds and their energy-band structure have been calculated and compared
with the existing data in the literature. General trends for the ground-state
parameters, the electronic energy-bands and transition energies for all the
fluorides considered are given and discussed in details. Moreover, for the
first time results for have been presented
Spin density wave dislocation in chromium probed by coherent x-ray diffraction
We report on the study of a magnetic dislocation in pure chromium. Coherent
x-ray diffraction profiles obtained on the incommensurate Spin Density Wave
(SDW) reflection are consistent with the presence of a dislocation of the
magnetic order, embedded at a few micrometers from the surface of the sample.
Beyond the specific case of magnetic dislocations in chromium, this work may
open up a new method for the study of magnetic defects embedded in the bulk.Comment: 8 pages, 7 figure
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays
By analyzing about 33 data sample collected at and around 3.773
GeV with the BES-II detector at the BEPC collider, we directly measure the
branching fractions for the neutral and charged inclusive semimuonic decays
to be and , and determine the ratio of the two branching
fractions to be
A study of charged kappa in
Based on events collected by BESII, the decay
is studied. In the invariant mass
spectrum recoiling against the charged , the charged
particle is found as a low mass enhancement. If a Breit-Wigner function of
constant width is used to parameterize the kappa, its pole locates at MeV/. Also in this channel,
the decay is observed for the first time.
Its branching ratio is .Comment: 14 pages, 4 figure
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