2,496 research outputs found
Light emission by accelerated electric, toroidal and anapole dipolar sources
Emission of electromagnetic radiation by accelerated particles with electric,
toroidal and anapole dipole moments is analyzed. It is shown that ellipticity
of the emitted light can be used to differentiate between electric and toroidal
dipole sources, and that anapoles, elementary neutral non-radiating
configurations, which consist of electric and toroidal dipoles, can emit light
under uniform acceleration. The existence of non-radiating configurations in
electrodynamics implies that it is impossible to fully determine the internal
makeup of the emitter given only the distribution of the emitted light. Here we
demonstrate that there is a loop-hole in this `inverse source problem'. Our
results imply that there may be a whole range of new phenomena to be discovered
by studying the electromagnetic response of matter under acceleration.Comment: Change from previous version. Further corrections to figure 1. Much
more calculations in the main paper. Added a section on ellipticit
Preliminary Results on gamma gamma -> Ks K pi from CLEO
We analyzed 13.8 fb^{-1} of the integrated e+e- luminosity collected at 10.6
GeV center-of-mass energy with the CLEO II and II.V detectors to study
exclusive two-photon production of single hadronic resonances. We searched for
hadrons decaying into Ks K pi when both leptons remain undetected. In this
analysis we studied the detection efficiency and evaluated systematic errors
using independent data samples. We estimated 90% CL upper limits on the
products of the two-photon partial widths of (pseudo)scalar hadrons with masses
below 1.7 GeV/c2 and their branching fractions into Ks K pi. Our preliminary
results are marginally consistent with the first observation of eta(1440) in
two-photon collisions by the L3 experiment.Comment: 4 pages, 1 figure, proceedings contribution for PANIC'0
In situ visualization of Ni-Nb bulk metallic glasses phase transition
We report the results of the Ni-based bulk metallic glass structural
evolution and crystallization behavior in situ investigation. The X-ray
diffraction (XRD), transmission electron microscopy (TEM), nano-beam
diffraction (NBD), differential scanning calorimetry (DSC), radial distribution
function (RDF) and scanning probe microscopy/spectroscopy (STM/STS) techniques
were applied to analyze the structure and electronic properties of Ni63.5Nb36.5
glasses before and after crystallization. It was proved that partial surface
crystallization of Ni63.5Nb36.5 can occur at the temperature lower than for the
full sample crystallization. According to our STM measurements the primary
crystallization is originally starting with the Ni3Nb phase formation. It was
shown that surface crystallization drastically differs from the bulk
crystallization due to the possible surface reconstruction. The mechanism of
Ni63.5Nb36.5 glass alloy 2D-crystallization was suggested, which corresponds to
the local metastable (3x3)-Ni(111) surface phase formation. The possibility of
different surface nano-structures development by the annealing of the
originally glassy alloy in ultra high vacuum at the temperature lower, than the
crystallization temperature was shown. The increase of mean square surface
roughness parameter Rq while moving from glassy to fully crystallized state can
be caused by concurrent growth of Ni3Nb and Ni6Nb7 bulk phases. The simple
empirical model for the estimation of Ni63.5Nb36.5 cluster size was suggested,
and the obtained values (7.64 A, 8.08 A) are in good agreement with STM
measurements data (8 A-10 A)
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