69,222 research outputs found
Detection of Charged MSSM Higgs Bosons at CERN LEP-II and NLC
We study the possibility of detecting the charged Higgs bosons predicted in
the Minimal Supersymmetric Standard Model , with the reactions
, using the
helicity formalism. We analyze the region of parameter space
where could be detected in the limit when
is large. The numerical computation is done for the energie which
is expected to be available at LEP-II ( GeV) and for a possible
Next Linear Collider ( GeV).Comment: Latex file and 5 figure
Combined grazing incidence RBS and TEM analysis of luminescent nano-SiGe/SiO2 multilayers.
Multilayer structures with five periods of amorphous SiGe nanoparticles/SiO2 layers with different thickness were deposited by Low Pressure Chemical Vapor Deposition and annealed to crystallize the SiGe nanoparticles. The use of grazing incidence RBS was necessary to obtain sufficient depth resolution to separate the signals arising from the individual layers only a few nm thick. The average size and areal density of the embedded SiGe nanoparticles as well as the oxide interlayer thickness were determined from the RBS spectra. Details of eventual composition changes and diffusion processes caused by the annealing processes were also studied. Transmission Electron Microscopy was used to obtain complementary information on the structural parameters of the samples in order to check the information yielded by RBS. The study revealed that annealing at 900 °C for 60 s, enough to crystallize the SiGe nanoparticles, leaves the structure unaltered if the interlayer thickness is around 15 nm or higher
Polydispersity Effects in the Dynamics and Stability of Bubbling Flows
The occurrence of swarms of small bubbles in a variety of industrial systems
enhances their performance. However, the effects that size polydispersity may
produce on the stability of kinematic waves, the gain factor, mean bubble
velocity, kinematic and dynamic wave velocities is, to our knowledge, not yet
well established. We found that size polydispersity enhances the stability of a
bubble column by a factor of about 23% as a function of frequency and for a
particular type of bubble column. In this way our model predicts effects that
might be verified experimentally but this, however, remain to be assessed. Our
results reinforce the point of view advocated in this work in the sense that a
description of a bubble column based on the concept of randomness of a bubble
cloud and average properties of the fluid motion, may be a useful approach that
has not been exploited in engineering systems.Comment: 11 pages, 2 figures, presented at the 3rd NEXT-SigmaPhi International
Conference, 13-18 August, 2005, Kolymbari, Cret
Dynamical quarks effects on the gluon propagation and chiral symmetry restoration
We exploit the recent lattice results for the infrared gluon propagator with
light dynamical quarks and solve the gap equation for the quark propagator.
Chiral symmetry breaking and confinement (intimately tied with the analytic
properties of QCD Schwinger functions) order parameters are then studied.Comment: Contribution to QCD-TNT-III: "From quarks and gluons to hadronic
matter: A bridge too far?
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