9,512 research outputs found
Probing neutral top-pion via a flavor-changing process
In the framework of topcolor-assisted-technicolor model(TC2), we study a
flavor-changing neutral top-pion production process . The study shows that there exists a resonance effect
which can enhance the cross section up to a few fb even tens fb. For a yearly
luminosity 100 at future linear colliders, there might be hundreds
even thousands events to be produced. On the other hand, the background of such
flavor-changing process is very clean due to the GIM mechanism in SM . With
such sufficient events and clean background, neutral toppion could be detected
at future linear colliders with high center of energy and luminosity. Our study
provides a possible way to test TC2 model.Comment: 10 pages, 4 figures,has been accepted by Phys.Rev.
Topological quantum phase transition in an extended Kitaev spin model
We study the quantum phase transition between Abelian and non-Abelian phases
in an extended Kitaev spin model on the honeycomb lattice, where the periodic
boundary condition is applied by placing the lattice on a torus. Our analytical
results show that this spin model exhibits a continuous quantum phase
transition. Also, we reveal the relationship between bipartite entanglement and
the ground-state energy. Our approach directly shows that both the entanglement
and the ground-state energy can be used to characterize the topological quantum
phase transition in the extended Kitaev spin model.Comment: 9 Pages, 4 figure
High-resolution (375 m) cloud microstructure as seen from the NPP/VIIRS satellite imager
VIIRS (Visible Infrared Imaging Radiometer Suite), onboard the Suomi NPP
(National Polar-orbiting Partnership) satellite, has an improved resolution of
750 m with respect to the 1000 m of the Moderate Resolution Imaging
Spectroradiometer for the channels that allow retrieving cloud
microphysical parameters such as cloud drop effective radius (<i>r</i><sub>e</sub>).
VIIRS also has an imager with five channels of double resolution of 375 m,
which was not designed for retrieving cloud products. A methodology for a
high-resolution retrieval of <i>r</i><sub>e</sub> and microphysical presentation of the
cloud field based on the VIIRS imager was developed and evaluated with
respect to MODIS in this study. The tripled microphysical resolution with
respect to MODIS allows obtaining new insights for cloud–aerosol
interactions, especially at the smallest cloud scales, because the VIIRS
imager can resolve the small convective elements that are sub-pixel for
MODIS cloud products. Examples are given for new insights into ship tracks in
marine stratocumulus, pollution tracks from point and diffused sources in
stratocumulus and cumulus clouds over land, deep tropical convection in
pristine air mass over ocean and land, tropical clouds that develop in smoke
from forest fires and in heavy pollution haze over densely populated regions
in southeastern Asia, and for pyro-cumulonimbus clouds.
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It is found that the VIIRS imager provides more robust physical
interpretation and refined information for cloud and aerosol microphysics as
compared to MODIS, especially in the initial stage of cloud formation. VIIRS
is found to identify significantly more fully cloudy pixels when small
boundary layer convective elements are present. This, in turn, allows for a
better quantification of cloud–aerosol interactions and impacts on
precipitation-forming processes
A Feasibility Study of SSVEP-Based Passive Training on an Ankle Rehabilitation Robot
Objective: This study aims to establish a steady-state visual evoked potential- (SSVEP-) based passive training protocol on an ankle rehabilitation robot and validate its feasibility. Method: This paper combines SSVEP signals and the virtual reality circumstance through constructing information transmission loops between brains and ankle robots. The robot can judge motion intentions of subjects and trigger the training when subjects pay their attention on one of the four flickering circles. The virtual reality training circumstance provides real-time visual feedback of ankle rotation. Result: All five subjects succeeded in conducting ankle training based on the SSVEP-triggered training strategy following their motion intentions. The lowest success rate is 80%, and the highest one is 100%. The lowest information transfer rate (ITR) is 11.5 bits/min when the biggest one of the robots for this proposed training is set as 24 bits/min. Conclusion: The proposed training strategy is feasible and promising to be combined with a robot for ankle rehabilitation. Future work will focus on adopting more advanced data process techniques to improve the reliability of intention detection and investigating how patients respond to such a training strategy
Poling effect on distribution of quenched random fields in a uniaxial relaxor ferroelectric
The frequency dependence of the dielectric permitivity's maximum has been
studied for poled and unpoled doped relaxor strontium barium niobate
(SBN-61:Cr). In both cases the maximum
found is broad and the frequency dispersion is strong. The present view of
random fields compensation in the unpoled sample is not suitable for explaining
this experimental result. We propose a new mechanism where the dispersion of
quenched random electric fields, affecting the nanodomains, is minimized after
poling. We test our proposal by numerical simulations on a random field Ising
model. Results obtained are in agreement with the polarization's measurements
presented by Granzow et al. [Phys. Rev. Lett {\bf 92}, 065701 (2004)].Comment: 7 pages, 4 figure
Production of the neutral top-pion in association with a high- jet at the
In the framework of the topcolor-assisted technicolor model, we study
production of the neutral top-pion in association with a
high- jet at the , which proceeds via the partonic processes
, ,
, , and . We find
that it is very challenging to detect the neutral top-pion via
the process , while the
possible signatures of might be detected via the process
at the .Comment: 13 pages, 4 figures; typos correcte
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